1
|
Bayer A, Child SJ, Malik HS, Geballe AP. A single polymorphic residue in humans underlies species-specific restriction of HSV-1 by the antiviral protein MxB. J Virol 2023; 97:e0083023. [PMID: 37796130 PMCID: PMC10617587 DOI: 10.1128/jvi.00830-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/23/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Herpesviruses present a major global disease burden. Understanding the host cell mechanisms that block viral infections, as well as how viruses can evolve to counteract these host defenses, is critically important for understanding viral disease pathogenesis. This study reveals that the major human variant of the antiviral protein myxovirus resistance protein B (MxB) inhibits the human pathogen herpes simplex virus (HSV-1), whereas a minor human variant and orthologous MxB genes from even closely related primates do not. Thus, in contrast to the many antagonistic virus-host interactions in which the virus is successful in thwarting the host's defense systems, here the human gene appears to be at least temporarily winning at this interface of the primate-herpesvirus evolutionary arms race. Our findings further show that a polymorphism at amino acid 83 in a small fraction of the human population is sufficient to abrogate MxB's ability to inhibit HSV-1, which could have important implications for human susceptibility to HSV-1 pathogenesis.
Collapse
Affiliation(s)
- Avraham Bayer
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Stephanie J. Child
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Harmit S. Malik
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Adam P. Geballe
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, USA
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| |
Collapse
|
2
|
Olson AT, Kang Y, Ladha AM, Zhu S, Lim CB, Nabet B, Lagunoff M, Gujral TS, Geballe AP. Polypharmacology-based kinome screen identifies new regulators of KSHV reactivation. PLoS Pathog 2023; 19:e1011169. [PMID: 37669313 PMCID: PMC10503724 DOI: 10.1371/journal.ppat.1011169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 09/15/2023] [Accepted: 08/16/2023] [Indexed: 09/07/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) causes several human diseases including Kaposi's sarcoma (KS), a leading cause of cancer in Africa and in patients with AIDS. KS tumor cells harbor KSHV predominantly in a latent form, while typically <5% contain lytic replicating virus. Because both latent and lytic stages likely contribute to cancer initiation and progression, continued dissection of host regulators of this biological switch will provide insights into fundamental pathways controlling the KSHV life cycle and related disease pathogenesis. Several cellular protein kinases have been reported to promote or restrict KSHV reactivation, but our knowledge of these signaling mediators and pathways is incomplete. We employed a polypharmacology-based kinome screen to identify specific kinases that regulate KSHV reactivation. Those identified by the screen and validated by knockdown experiments included several kinases that enhance lytic reactivation: ERBB2 (HER2 or neu), ERBB3 (HER3), ERBB4 (HER4), MKNK2 (MNK2), ITK, TEC, and DSTYK (RIPK5). Conversely, ERBB1 (EGFR1 or HER1), MKNK1 (MNK1) and FRK (PTK5) were found to promote the maintenance of latency. Mechanistic characterization of ERBB2 pro-lytic functions revealed a signaling connection between ERBB2 and the activation of CREB1, a transcription factor that drives KSHV lytic gene expression. These studies provided a proof-of-principle application of a polypharmacology-based kinome screen for the study of KSHV reactivation and enabled the discovery of both kinase inhibitors and specific kinases that regulate the KSHV latent-to-lytic replication switch.
Collapse
Affiliation(s)
- Annabel T. Olson
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Yuqi Kang
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Anushka M. Ladha
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Songli Zhu
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Chuan Bian Lim
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Behnam Nabet
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Michael Lagunoff
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Taranjit S. Gujral
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
| | - Adam P. Geballe
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Division of Clinical Research, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| |
Collapse
|
3
|
Bayer A, Child SJ, Malik HS, Geballe AP. A single polymorphic residue in humans underlies species-specific restriction of HSV-1 by the antiviral protein MxB. bioRxiv 2023:2023.05.30.542951. [PMID: 37398298 PMCID: PMC10312577 DOI: 10.1101/2023.05.30.542951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Myxovirus resistance proteins (MxA and MxB) are interferon-induced proteins that exert antiviral activity against a diverse range of RNA and DNA viruses. In primates, MxA has been shown to inhibit myxoviruses, bunyaviruses, and hepatitis B virus, whereas MxB restricts retroviruses and herpesviruses. As a result of their conflicts with viruses, both genes have been undergoing diversifying selection during primate evolution. Here, we investigate how MxB evolution in primates has affected its restriction of herpesviruses. In contrast to human MxB, we find that most primate orthologs, including the closely related chimpanzee MxB, do not inhibit HSV-1 replication. However, all primate MxB orthologs tested restrict human cytomegalovirus. Through the generation of human and chimpanzee MxB chimeras we show that a single residue, M83, is the key determinant of restriction of HSV-1 replication. Humans are the only primate species known to encode a methionine at this position, whereas most other primate species encode a lysine. Residue 83 is also the most polymorphic residue in MxB in human populations, with M83 being the most common variant. However, ∼2.5% of human MxB alleles encode a threonine at this position, which does not restrict HSV-1. Thus, a single amino acid variant in MxB, which has recently risen to high frequency in humans, has endowed humans with HSV-1 antiviral activity. Importance Herpesviruses present a major global disease burden. Understanding the host cell mechanisms that block viral infections as well as how viruses can evolve to counteract these host defenses is critically important for understanding viral disease pathogenesis, and for developing therapeutic tools aimed at treating or preventing viral infections. Additionally, understanding how these host and viral mechanisms adapt to counter one another can aid in identifying the risks of, and barriers to, cross-species transmission events. As highlighted by the recent SARS-CoV-2 pandemic, episodic transmission events can have severe consequences for human health. This study reveals that the major human variant of the antiviral protein MxB inhibits the human pathogen HSV-1, whereas human minor variants and orthologous MxB genes from even closely related primates do not. Thus, in contrast to the many antagonistic virus-host interactions in which the virus is successful in thwarting the defense systems of their native hosts, in this case the human gene appears to be at least temporarily winning at this interface of the primate-herpesviral evolutionary arms race. Our findings further show that a polymorphism at amino acid 83 in a small fraction of the human population is sufficient to abrogate MxB's ability to inhibit HSV-1, which could have important implications for human susceptibility to HSV-1 pathogenesis.
Collapse
Affiliation(s)
- Avraham Bayer
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Stephanie J. Child
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Harmit S. Malik
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Howard Hughes Medical Institute, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Adam P. Geballe
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Departments of Medicine and Microbiology, University of Washington, Seattle WA, USA
| |
Collapse
|
4
|
Olson AT, Kang Y, Ladha AM, Lim CB, Lagunoff M, Gujral TS, Geballe AP. Polypharmacology-based kinome screen identifies new regulators of KSHV reactivation. bioRxiv 2023:2023.02.01.526589. [PMID: 36778430 PMCID: PMC9915688 DOI: 10.1101/2023.02.01.526589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) causes several human diseases including Kaposi's sarcoma (KS), a leading cause of cancer in Africa and in patients with AIDS. KS tumor cells harbor KSHV predominantly in a latent form, while typically <5% contain lytic replicating virus. Because both latent and lytic stages likely contribute to cancer initiation and progression, continued dissection of host regulators of this biological switch will provide insights into fundamental pathways controlling the KSHV life cycle and related disease pathogenesis. Several cellular protein kinases have been reported to promote or restrict KSHV reactivation, but our knowledge of these signaling mediators and pathways is incomplete. We employed a polypharmacology-based kinome screen to identifiy specific kinases that regulate KSHV reactivation. Those identified by the screen and validated by knockdown experiments included several kinases that enhance lytic reactivation: ERBB2 (HER2 or neu ), ERBB3 (HER3), ERBB4 (HER4), MKNK2 (MNK2), ITK, TEC, and DSTYK (RIPK5). Conversely, ERBB1 (EGFR1 or HER1), MKNK1 (MNK1) and FRK (PTK5) were found to promote the maintenance of latency. Mechanistic characterization of ERBB2 pro-lytic functions revealed a signaling connection between ERBB2 and the activation of CREB1, a transcription factor that drives KSHV lytic gene expression. These studies provided a proof-of-principle application of a polypharmacology-based kinome screen for the study of KSHV reactivation and enabled the discovery of both kinase inhibitors and specific kinases that regulate the KSHV latent-to-lytic replication switch. Author Summary Kaposi's sarcoma-associated herpesvirus (KSHV) causes Kaposi's sarcoma, a cancer particularly prevalent in Africa. In cancer cells, the virus persists in a quiescent form called latency, in which only a few viral genes are made. Periodically, the virus switches into an active replicative cycle in which most of the viral genes are made and new virus is produced. What controls the switch from latency to active replication is not well understood, but cellular kinases, enzymes that control many cellular processes, have been implicated. Using a cell culture model of KSHV reactivation along with an innovative screening method that probes the effects of many cellular kinases simultaneously, we identified drugs that significantly limit KSHV reactivation, as well as specific kinases that either enhance or restrict KSHV replicative cycle. Among these were the ERBB kinases which are known to regulate growth of cancer cells. Understanding how these and other kinases contribute to the switch leading to production of more infectious virus helps us understand the mediators and mechanisms of KSHV diseases. Additionally, because kinase inhibitors are proving to be effective for treating other diseases including some cancers, identifying ones that restrict KSHV replicative cycle may lead to new approaches to treating KSHV-related diseases.
Collapse
Affiliation(s)
- Annabel T. Olson
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
| | - Yuqi Kang
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
| | - Anushka M. Ladha
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Chuan Bian Lim
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
| | - Michael Lagunoff
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Taran S. Gujral
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Adam P. Geballe
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
- Division of Clinical Research, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
- Department of Microbiology, University of Washington, Seattle, WA, USA
- Department of Medicine, University of Washington, Seattle, WA, USA
| |
Collapse
|
5
|
Banerjee S, Smith C, Geballe AP, Rothenburg S, Kitzman JO, Brennan G. Gene amplification acts as a molecular foothold to facilitate cross-species adaptation and evasion of multiple antiviral pathways. Virus Evol 2022; 8:veac105. [PMID: 36483110 PMCID: PMC9724558 DOI: 10.1093/ve/veac105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 10/06/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Cross-species spillover events are responsible for many of the pandemics in human history including COVID-19; however, the evolutionary mechanisms that enable these events are poorly understood. We have previously modeled this process using a chimeric vaccinia virus expressing the rhesus cytomegalovirus-derived protein kinase R (PKR) antagonist RhTRS1 in place of its native PKR antagonists: E3L and K3L (VACVΔEΔK + RhTRS1). Using this virus, we demonstrated that gene amplification of rhtrs1 occurred early during experimental evolution and was sufficient to fully rescue virus replication in partially resistant African green monkey (AGM) fibroblasts. Notably, this rapid gene amplification also allowed limited virus replication in otherwise completely non-permissive human fibroblasts, suggesting that gene amplification may act as a 'molecular foothold' to facilitate viral adaptation to multiple species. In this study, we demonstrate that there are multiple barriers to VACVΔEΔK + RhTRS1 replication in human cells, mediated by both PKR and ribonuclease L (RNase L). We experimentally evolved three AGM-adapted virus populations in human fibroblasts. Each population adapted to human cells bimodally, via an initial 10-fold increase in replication after only two passages followed by a second 10-fold increase in replication by passage 9. Using our Illumina-based pipeline, we found that some single nucleotide polymorphisms (SNPs) which had evolved during the prior AGM adaptation were rapidly lost, while thirteen single-base substitutions and short indels increased over time, including two SNPs unique to human foreskin fibroblast (HFF)-adapted populations. Many of these changes were associated with components of the viral RNA polymerase, although no variant was shared between all three populations. Taken together, our results demonstrate that rhtrs1 amplification was sufficient to increase viral tropism after passage in an 'intermediate species' and subsequently enabled the virus to adopt different, species-specific adaptive mechanisms to overcome distinct barriers to viral replication in AGM and human cells.
Collapse
Affiliation(s)
- Shefali Banerjee
- †Current address for SB: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Adam P Geballe
- Departments of Human Genetics and Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA,Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | | | - Jacob O Kitzman
- Departments of Microbiology and Medicine, University of Washington, Seattle, WA 98195, USA
| | | |
Collapse
|
6
|
Bottorff TA, Park H, Geballe AP, Subramaniam AR. Translational buffering by ribosome stalling in upstream open reading frames. PLoS Genet 2022; 18:e1010460. [PMID: 36315596 PMCID: PMC9648851 DOI: 10.1371/journal.pgen.1010460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 11/10/2022] [Accepted: 10/04/2022] [Indexed: 11/05/2022] Open
Abstract
Upstream open reading frames (uORFs) are present in over half of all human mRNAs. uORFs can potently regulate the translation of downstream open reading frames through several mechanisms: siphoning away scanning ribosomes, regulating re-initiation, and allowing interactions between scanning and elongating ribosomes. However, the consequences of these different mechanisms for the regulation of protein expression remain incompletely understood. Here, we performed systematic measurements on the uORF-containing 5' UTR of the cytomegaloviral UL4 mRNA to test alternative models of uORF-mediated regulation in human cells. We find that a terminal diproline-dependent elongating ribosome stall in the UL4 uORF prevents decreases in main ORF protein expression when ribosome loading onto the mRNA is reduced. This uORF-mediated buffering is insensitive to the location of the ribosome stall along the uORF. Computational kinetic modeling based on our measurements suggests that scanning ribosomes dissociate rather than queue when they collide with stalled elongating ribosomes within the UL4 uORF. We identify several human uORFs that repress main ORF protein expression via a similar terminal diproline motif. We propose that ribosome stalls in uORFs provide a general mechanism for buffering against reductions in main ORF translation during stress and developmental transitions.
Collapse
Affiliation(s)
- Ty A. Bottorff
- Basic Sciences Division and Computational Biology Program of the Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Biological Physics, Structure and Design Graduate Program, University of Washington, Seattle, Washington, United States of America
| | - Heungwon Park
- Basic Sciences Division and Computational Biology Program of the Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Adam P. Geballe
- Human Biology and Clinical Research Divisions, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Arvind Rasi Subramaniam
- Basic Sciences Division and Computational Biology Program of the Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Biological Physics, Structure and Design Graduate Program, University of Washington, Seattle, Washington, United States of America
| |
Collapse
|
7
|
Olson AT, Child SJ, Geballe AP. Antagonism of Protein Kinase R by Large DNA Viruses. Pathogens 2022; 11:pathogens11070790. [PMID: 35890034 PMCID: PMC9319463 DOI: 10.3390/pathogens11070790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 12/02/2022] Open
Abstract
Decades of research on vaccinia virus (VACV) have provided a wealth of insights and tools that have proven to be invaluable in a broad range of studies of molecular virology and pathogenesis. Among the challenges that viruses face are intrinsic host cellular defenses, such as the protein kinase R pathway, which shuts off protein synthesis in response to the dsRNA that accumulates during replication of many viruses. Activation of PKR results in phosphorylation of the α subunit of eukaryotic initiation factor 2 (eIF2α), inhibition of protein synthesis, and limited viral replication. VACV encodes two well-characterized antagonists, E3L and K3L, that can block the PKR pathway and thus enable the virus to replicate efficiently. The use of VACV with a deletion of the dominant factor, E3L, enabled the initial identification of PKR antagonists encoded by human cytomegalovirus (HCMV), a prevalent and medically important virus. Understanding the molecular mechanisms of E3L and K3L function facilitated the dissection of the domains, species-specificity, and evolutionary potential of PKR antagonists encoded by human and nonhuman CMVs. While remaining cognizant of the substantial differences in the molecular virology and replication strategies of VACV and CMVs, this review illustrates how VACV can provide a valuable guide for the study of other experimentally less tractable viruses.
Collapse
Affiliation(s)
- Annabel T. Olson
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Center, 1100 Fairview Ave N Seattle, P.O. Box 19024, Seattle, WA 98109, USA; (A.T.O.); (S.J.C.)
- Departments of Microbiology, University of Washington, Seattle, WA 98195, USA
| | - Stephanie J. Child
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Center, 1100 Fairview Ave N Seattle, P.O. Box 19024, Seattle, WA 98109, USA; (A.T.O.); (S.J.C.)
| | - Adam P. Geballe
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Center, 1100 Fairview Ave N Seattle, P.O. Box 19024, Seattle, WA 98109, USA; (A.T.O.); (S.J.C.)
- Departments of Microbiology, University of Washington, Seattle, WA 98195, USA
- Departments of Medicine, University of Washington, Seattle, WA 98195, USA
- Correspondence:
| |
Collapse
|
8
|
Schleiss MR, Fernández-Alarcón C, Hernandez-Alvarado N, Wang JB, Geballe AP, McVoy MA. Inclusion of the Guinea Pig Cytomegalovirus Pentameric Complex in a Live Virus Vaccine Aids Efficacy against Congenital Infection but Is Not Essential for Improving Maternal and Neonatal Outcomes. Viruses 2021; 13:v13122370. [PMID: 34960639 PMCID: PMC8706200 DOI: 10.3390/v13122370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/19/2021] [Accepted: 11/20/2021] [Indexed: 01/17/2023] Open
Abstract
The development of a vaccine against congenital human cytomegalovirus (HCMV) infection is a major priority. The pentameric complex (PC) of virion envelope proteins gH, gL, UL128, UL130, and UL131A is a key vaccine target. To determine the importance of immunity to the homologous PC encoded by guinea pig cytomegalovirus (GPCMV) in preventing congenital CMV, PC-intact and PC-deficient live-attenuated vaccines were generated and directly compared for immunogenicity and efficacy against vertical transmission in a vertical transmission model. A virulent PC-intact GPCMV (PC/intact) was modified by galK mutagenesis either to abrogate PC expression (PC/null; containing a frame-shift mutation in GP129, homolog of UL128) or to delete genes encoding three MHC Class I homologs and a protein kinase R (PKR) evasin while retaining the PC (3DX/Δ145). Attenuated vaccines were compared to sham immunization in a two-dose preconception subcutaneous inoculation regimen in GPCMV seronegative Hartley guinea pigs. Vaccines induced transient, low-grade viremia in 5/12 PC/intact-, 2/12 PC/null-, and 1/11 3DX/Δ145-vaccinated animals. Upon completion of the two-dose vaccine series, ELISA titers for the PC/intact group (geometic mean titer (GMT) 13,669) were not significantly different from PC/null (GMT 8127) but were significantly higher than for the 3DX/Δ145 group (GMT 6185; p < 0.01). Dams were challenged with salivary gland-adapted GPCMV in the second trimester. All vaccines conferred protection against maternal viremia. Newborn weights were significantly lower in sham-immunized controls (84.5 ± 2.4 g) compared to PC/intact (96 ± 2.3 g), PC/null (97.6 ± 1.9 g), or 3DX/Δ145 (93 ± 1.7) pups (p < 0.01). Pup mortality in sham-immunized controls was 29/40 (73%) and decreased to 1/44 (2.3%), 2/46 (4.3%), or 4/40 (10%) in PC/intact, PC/null, or 3DX/Δ145 groups, respectively (all p < 0.001 compared to control). Congenital GPCMV transmission occurred in 5/44 (11%), 16/46 (35%), or 29/38 (76%) of pups in PC/intact, PC/null, or 3DX/Δ145 groups, versus 36/40 (90%) in controls. For infected pups, viral loads were lower in pups born to vaccinated dams compared to controls. Sequence analysis demonstrated that infected pups in the vaccine groups had salivary gland-adapted GPCMV and not vaccine strain-specific sequences, indicating that congenital transmission was due to the challenge virus and not vaccine virus. We conclude that inclusion of the PC in a live, attenuated preconception vaccine improves immunogenicity and reduces vertical transmission, but PC-null vaccines are equal to PC-intact vaccines in reducing maternal viremia and protecting against GPCMV-related pup mortality.
Collapse
Affiliation(s)
- Mark R. Schleiss
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (C.F.-A.); (N.H.-A.)
- Correspondence: ; Tel.: +1-612-626-9913
| | - Claudia Fernández-Alarcón
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (C.F.-A.); (N.H.-A.)
| | - Nelmary Hernandez-Alvarado
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN 55455, USA; (C.F.-A.); (N.H.-A.)
| | - Jian Ben Wang
- Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, USA; (J.B.W.); (M.A.M.)
| | - Adam P. Geballe
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
| | - Michael A. McVoy
- Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, USA; (J.B.W.); (M.A.M.)
| |
Collapse
|
9
|
Zamora D, Krantz EM, Green ML, Joncas-Schronce L, Blazevic R, Edmison BC, Huang ML, Stevens-Ayers T, Jerome KR, Geballe AP, Boeckh M. Cytomegalovirus Humoral Response Against Epithelial Cell Entry-Mediated Infection in the Primary Infection Setting After Hematopoietic Cell Transplantation. J Infect Dis 2021; 221:1470-1479. [PMID: 31734696 DOI: 10.1093/infdis/jiz596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/12/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The influence of humoral immunity on the prevention of primary cytomegalovirus (CMV) infection after hematopoietic cell transplantation (HCT) is poorly understood. METHODS To determine whether neutralizing antibodies (nAbs) against CMV pentameric complex (PC)-mediated epithelial cell entry decrease CMV infection after HCT, samples were analyzed from a randomized controlled trial of CMV intravenous immunoglobulin (IVIG) prophylaxis. Weekly serum from 61 CMV donor-positive/recipient-negative (D+/R-) HCT patients (33 control, 28 CMV IVIG) was tested using a PC-entry nAb assay and quantitative CMV polymerase chain reaction (PCR). RESULTS There was a trend toward higher weekly PC-entry nAb titers (P = .07) and decreased CMV infection by PCR at viral load cutoffs of ≥1000 and ≥10 000 IU/mL in the CMV IVIG arm. High nAb titers were not significantly protective against CMV infection later after HCT in both study arms. Among CMV-infected patients, each log2 increase in nAb titer was associated with an average 0.2 log10 decrease in concurrent CMV viral load after infection (P = .001; adjusted for study arm). CONCLUSIONS This study provides initial support that CMV IVIG prophylaxis moderately enhances PC-entry nAB activity in D+/R- HCT recipients.
Collapse
Affiliation(s)
- Danniel Zamora
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| | - Elizabeth M Krantz
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Margaret L Green
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| | - Laurel Joncas-Schronce
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Rachel Blazevic
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Bradley C Edmison
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Meei-Li Huang
- Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Terry Stevens-Ayers
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Keith R Jerome
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Department of Laboratory Medicine, University of Washington, Seattle, Washington
| | - Adam P Geballe
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Departments of Medicine and Microbiology, University of Washington, Seattle, Washington
| | - Michael Boeckh
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.,Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington
| |
Collapse
|
10
|
Child SJ, Greninger AL, Geballe AP. Rapid adaptation to human protein kinase R by a unique genomic rearrangement in rhesus cytomegalovirus. PLoS Pathog 2021; 17:e1009088. [PMID: 33497413 PMCID: PMC7864422 DOI: 10.1371/journal.ppat.1009088] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/05/2021] [Accepted: 01/04/2021] [Indexed: 02/07/2023] Open
Abstract
Cytomegaloviruses (CMVs) are generally unable to cross species barriers, in part because prolonged coevolution with one host species limits their ability to evade restriction factors in other species. However, the limitation in host range is incomplete. For example, rhesus CMV (RhCMV) can replicate in human cells, albeit much less efficiently than in rhesus cells. Previously we reported that the protein kinase R (PKR) antagonist encoded by RhCMV, rTRS1, has limited activity against human PKR but is nonetheless necessary and sufficient to enable RhCMV replication in human fibroblasts (HF). We now show that knockout of PKR in human cells or treatment with the eIF2B agonist ISRIB, which overcomes the translational inhibition resulting from PKR activation, augments RhCMV replication in HF, indicating that human PKR contributes to the inefficiency of RhCMV replication in HF. Serial passage of RhCMV in HF reproducibly selected for viruses with improved ability to replicate in human cells. The evolved viruses contain an inverted duplication of the terminal 6.8 kb of the genome, including rTRS1. The duplication replaces ~11.8 kb just downstream of an internal sequence element, pac1-like, which is very similar to the pac1 cleavage and packaging signal found near the terminus of the genome. Plaque-purified evolved viruses produced at least twice as much rTRS1 as the parental RhCMV and blocked the PKR pathway more effectively in HF. Southern blots revealed that unlike the parental RhCMV, viruses with the inverted duplication isomerize in a manner similar to HCMV and other herpesviruses that have internal repeat sequences. The apparent ease with which this duplication event occurs raises the possibility that the pac1-like site, which is conserved in Old World monkey CMV genomes, may serve a function in facilitating rapid adaptation to evolutionary obstacles.
Collapse
Affiliation(s)
- Stephanie J. Child
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Alexander L. Greninger
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Adam P. Geballe
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Departments of Medicine and Microbiology, University of Washington, Seattle, Washington, United States of America
| |
Collapse
|
11
|
Limaye AP, Green ML, Edmison BC, Stevens-Ayers T, Chatterton-Kirchmeier S, Geballe AP, Singh N, Boeckh M. Prospective Assessment of Cytomegalovirus Immunity in High-Risk Donor-Seropositive/Recipient-Seronegative Liver Transplant Recipients Receiving Either Preemptive Therapy or Antiviral Prophylaxis. J Infect Dis 2020; 220:752-760. [PMID: 31112280 DOI: 10.1093/infdis/jiz181] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 04/22/2019] [Indexed: 12/29/2022] Open
Abstract
The differential impact of preemptive therapy (PET) and antiviral prophylaxis (AP) on development of cytomegalovirus (CMV)-specific neutralizing antibody (nAb) and T-cell responses have not previously been directly compared in high-risk donor-seropositive/recipient-seronegative (D+R-) organ transplant recipients. We prospectively assessed T-cell and nAb responses 3 months after transplantation in cohorts of high-risk D+R- liver transplant recipients who received either PET (n = 15) or AP (n = 25) and a control group of CMV-seropositive transplant recipients (R+) (AP; n = 24). CMV phosphoprotein 65 (pp65)- and immediate early protein 1-specific multifunctional T-cell responses were determined by means of intracellular cytokine staining and nAbs against BADrUL131-Y4 CMV in adult retinal pigment epithelial cell line-19 human epithelial cells; nAbs were detected in 8 of 12 (67%) in the PET group, none of 17 in the AP group, and 20 of 22 (91%) in the R+ group. Multifunctional CD8 and CD4 T-cell responses to pp65 were generally similar between PET and R+ groups, and lower for the AP group; multifunctional CD4 responses were similar across all groups. Among D+R- liver transplant recipients, PET was associated with the development of greater nAb and multifunctional CD8 T-cell responses compared with AP, providing a potential mechanism to explain the relative protection against late-onset disease with PET. Future studies are needed to define specific immune parameters predictive of late-onset CMV disease with AP.
Collapse
Affiliation(s)
- Ajit P Limaye
- Department of Medicine, University of Washington, Seattle
| | - Margaret L Green
- Department of Medicine, University of Washington, Seattle.,Fred Hutchinson Cancer Research Center, Seattle
| | | | - Terry Stevens-Ayers
- Fred Hutchinson Cancer Research Center, Seattle.,Program in Infectious Diseases, VA Pittsburgh Healthcare System and University of Pittsburgh, Pennsylvania
| | - Sam Chatterton-Kirchmeier
- Fred Hutchinson Cancer Research Center, Seattle.,Program in Infectious Diseases, VA Pittsburgh Healthcare System and University of Pittsburgh, Pennsylvania
| | - Adam P Geballe
- Department of Medicine, University of Washington, Seattle.,Fred Hutchinson Cancer Research Center, Seattle.,Program in Infectious Diseases, VA Pittsburgh Healthcare System and University of Pittsburgh, Pennsylvania
| | - Nina Singh
- Program in Infectious Diseases, VA Pittsburgh Healthcare System and University of Pittsburgh, Pennsylvania
| | - Michael Boeckh
- Department of Medicine, University of Washington, Seattle.,Fred Hutchinson Cancer Research Center, Seattle.,Program in Infectious Diseases, VA Pittsburgh Healthcare System and University of Pittsburgh, Pennsylvania
| |
Collapse
|
12
|
Zamora D, Green ML, Krantz E, Joncas-Schronce L, Edmison BC, Stevens-Ayers TL, Geballe AP, Boeckh MJ. Cytomegalovirus (CMV) Pentameric Complex (PC) Neutralizing Antibodies (nAb) from a Randomized, Controlled Trial of CMV-Specific Intravenous Immunoglobulin (IVIG) for the Prevention of Primary CMV Infection after Hematopoietic Cell Transplantation (HCT). Biol Blood Marrow Transplant 2019. [DOI: 10.1016/j.bbmt.2018.12.557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
13
|
Hickson SE, Margineantu D, Hockenbery DM, Simon JA, Geballe AP. Inhibition of vaccinia virus replication by nitazoxanide. Virology 2018; 518:398-405. [PMID: 29625403 DOI: 10.1016/j.virol.2018.03.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/22/2018] [Accepted: 03/23/2018] [Indexed: 12/27/2022]
Abstract
Nitazoxanide (NTZ) is an FDA-approved anti-protozoal drug that inhibits several bacteria and viruses as well. However, its effect on poxviruses is unknown. Therefore, we investigated the impact of NTZ on vaccinia virus (VACV). We found that NTZ inhibits VACV production with an EC50 of ~2 μM, a potency comparable to that reported for several other viruses. The inhibitory block occurs early during the viral life cycle, prior to viral DNA replication. The mechanism of viral inhibition is likely not due to activation of intracellular innate immune pathways, such as protein kinase R (PKR) or interferon signaling, contrary to what has been suggested to mediate the effects of NTZ against some other viruses. Rather, our finding that addition of exogenous palmitate partially rescues VACV production from the inhibitory effect of NTZ suggests that NTZ impedes adaptations in cellular metabolism that are needed for efficient completion of the VACV replication cycle.
Collapse
Affiliation(s)
- Sarah E Hickson
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States; Department of Microbiology, University of Washington, Seattle, WA 98115, United States
| | - Daciana Margineantu
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States
| | - David M Hockenbery
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States; Department of Medicine, University of Washington, Seattle, WA 98115, United States
| | - Julian A Simon
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States
| | - Adam P Geballe
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States; Department of Microbiology, University of Washington, Seattle, WA 98115, United States; Department of Medicine, University of Washington, Seattle, WA 98115, United States.
| |
Collapse
|
14
|
Mouna L, Hernandez E, Bonte D, Brost R, Amazit L, Delgui LR, Brune W, Geballe AP, Beau I, Esclatine A. Analysis of the role of autophagy inhibition by two complementary human cytomegalovirus BECN1/Beclin 1-binding proteins. Autophagy 2016; 12:327-42. [PMID: 26654401 DOI: 10.1080/15548627.2015.1125071] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Autophagy is activated early after human cytomegalovirus (HCMV) infection but, later on, the virus blocks autophagy. Here we characterized 2 HCMV proteins, TRS1 and IRS1, which inhibit autophagy during infection. Expression of either TRS1 or IRS1 was able to block autophagy in different cell lines, independently of the EIF2S1 kinase, EIF2AK2/PKR. Instead, TRS1 and IRS1 interacted with the autophagy protein BECN1/Beclin 1. We mapped the BECN1-binding domain (BBD) of IRS1 and TRS1 and found it to be essential for autophagy inhibition. Mutant viruses that express only IRS1 or TRS1 partially controlled autophagy, whereas a double mutant virus expressing neither protein stimulated autophagy. A mutant virus that did not express IRS1 and expressed a truncated form of TRS1 in which the BBD was deleted, failed to control autophagy. However, this mutant virus had similar replication kinetics as wild-type virus, suggesting that autophagy inhibition is not critical for viral replication. In fact, using pharmacological modulators of autophagy and inhibition of autophagy by shRNA knockdown, we discovered that stimulating autophagy enhanced viral replication. Conversely, inhibiting autophagy decreased HCMV infection. Thus, our results demonstrate a new proviral role of autophagy for a DNA virus.
Collapse
Affiliation(s)
- Lina Mouna
- a Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay , Gif sur Yvette , France
| | - Eva Hernandez
- a Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay , Gif sur Yvette , France
| | - Dorine Bonte
- b CNRS UMR8200, Univ Paris-Sud, Institut Gustave Roussy , Villejuif , France
| | - Rebekka Brost
- c Heinrich Pette Institute, Leibniz Institute for Experimental Virology , Hamburg , Germany
| | - Larbi Amazit
- d INSERM UMR-S-1185, Faculty of Medicine , Univ Paris-Sud , Le Kremlin Bicêtre , France
| | - Laura R Delgui
- e Instituto de Histología y Embriología (IHEM), Universidad Nacional de Cuyo-CONICET , Mendoza , Argentina
| | - Wolfram Brune
- c Heinrich Pette Institute, Leibniz Institute for Experimental Virology , Hamburg , Germany
| | - Adam P Geballe
- f Fred Hutchinson Cancer Research Center and University of Washington , Seattle , WA , USA
| | - Isabelle Beau
- d INSERM UMR-S-1185, Faculty of Medicine , Univ Paris-Sud , Le Kremlin Bicêtre , France
| | - Audrey Esclatine
- a Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay , Gif sur Yvette , France
| |
Collapse
|
15
|
Carpentier KS, Esparo NM, Child SJ, Geballe AP. A Single Amino Acid Dictates Protein Kinase R Susceptibility to Unrelated Viral Antagonists. PLoS Pathog 2016; 12:e1005966. [PMID: 27780231 PMCID: PMC5079575 DOI: 10.1371/journal.ppat.1005966] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/30/2016] [Indexed: 02/07/2023] Open
Abstract
During millions of years of coevolution with their hosts, cytomegaloviruses (CMVs) have succeeded in adapting to overcome host-specific immune defenses, including the protein kinase R (PKR) pathway. Consequently, these adaptations may also contribute to the inability of CMVs to cross species barriers. Here, we provide evidence that the evolutionary arms race between the antiviral factor PKR and its CMV antagonist TRS1 has led to extensive differences in the species-specificity of primate CMV TRS1 proteins. Moreover, we identify a single residue in human PKR that when mutated to the amino acid present in African green monkey (Agm) PKR (F489S) is sufficient to confer resistance to HCMVTRS1. Notably, this precise molecular determinant of PKR resistance has evolved under strong positive selection among primate PKR alleles and is positioned within the αG helix, which mediates the direct interaction of PKR with its substrate eIF2α. Remarkably, this same residue also impacts sensitivity to K3L, a poxvirus-encoded pseudosubstrate that structurally mimics eIF2α. Unlike K3L, TRS1 has no homology to eIF2α, suggesting that unrelated viral genes have convergently evolved to target this critical region of PKR. Despite its functional importance, the αG helix exhibits extraordinary plasticity, enabling adaptations that allow PKR to evade diverse viral antagonists while still maintaining its critical interaction with eIF2α.
Collapse
Affiliation(s)
- Kathryn S. Carpentier
- Departments of Microbiology and Medicine, University of Washington, Seattle Washington, and Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Nicolle M. Esparo
- Departments of Microbiology and Medicine, University of Washington, Seattle Washington, and Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Stephanie J. Child
- Departments of Microbiology and Medicine, University of Washington, Seattle Washington, and Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Adam P. Geballe
- Departments of Microbiology and Medicine, University of Washington, Seattle Washington, and Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington
- * E-mail:
| |
Collapse
|
16
|
Gray EE, Winship D, Snyder JM, Child SJ, Geballe AP, Stetson DB. The AIM2-like Receptors Are Dispensable for the Interferon Response to Intracellular DNA. Immunity 2016; 45:255-66. [PMID: 27496731 DOI: 10.1016/j.immuni.2016.06.015] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/22/2016] [Accepted: 05/05/2016] [Indexed: 11/27/2022]
Abstract
Detection of intracellular DNA triggers activation of the STING-dependent interferon-stimulatory DNA (ISD) pathway, which is essential for antiviral responses. Multiple DNA sensors have been proposed to activate this pathway, including AIM2-like receptors (ALRs). Whether the ALRs are essential for activation of this pathway remains unknown. To rigorously explore the function of ALRs, we generated mice lacking all 13 ALR genes. We found that ALRs are dispensable for the type I interferon (IFN) response to transfected DNA ligands, DNA virus infection, and lentivirus infection. We also found that ALRs do not contribute to autoimmune disease in the Trex1(-/-) mouse model of Aicardi-Goutières Syndrome. Finally, CRISPR-mediated disruption of the human AIM2-like receptor IFI16 in primary fibroblasts revealed that IFI16 is not essential for the IFN response to human cytomegalovirus infection. Our findings indicate that ALRs are dispensable for the ISD response and suggest that alternative functions for these receptors should be explored.
Collapse
Affiliation(s)
- Elizabeth E Gray
- Department of Immunology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Damion Winship
- Department of Immunology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Jessica M Snyder
- Department of Comparative Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Stephanie J Child
- Departments of Microbiology and Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA; Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Adam P Geballe
- Departments of Microbiology and Medicine, University of Washington School of Medicine, Seattle, WA, 98195, USA; Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Daniel B Stetson
- Department of Immunology, University of Washington School of Medicine, Seattle, WA, 98195, USA.
| |
Collapse
|
17
|
Daugherty MD, Schaller AM, Geballe AP, Malik HS. Evolution-guided functional analyses reveal diverse antiviral specificities encoded by IFIT1 genes in mammals. eLife 2016; 5. [PMID: 27240734 PMCID: PMC4887208 DOI: 10.7554/elife.14228] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/13/2016] [Indexed: 12/21/2022] Open
Abstract
IFIT (interferon-induced with tetratricopeptide repeats) proteins are critical mediators of mammalian innate antiviral immunity. Mouse IFIT1 selectively inhibits viruses that lack 2'O-methylation of their mRNA 5' caps. Surprisingly, human IFIT1 does not share this antiviral specificity. Here, we resolve this discrepancy by demonstrating that human and mouse IFIT1 have evolved distinct functions using a combination of evolutionary, genetic and virological analyses. First, we show that human IFIT1 and mouse IFIT1 (renamed IFIT1B) are not orthologs, but are paralogs that diverged >100 mya. Second, using a yeast genetic assay, we show that IFIT1 and IFIT1B proteins differ in their ability to be suppressed by a cap 2'O-methyltransferase. Finally, we demonstrate that IFIT1 and IFIT1B have divergent antiviral specificities, including the discovery that only IFIT1 proteins inhibit a virus encoding a cap 2'O-methyltransferase. These functional data, combined with widespread turnover of mammalian IFIT genes, reveal dramatic species-specific differences in IFIT-mediated antiviral repertoires.
Collapse
Affiliation(s)
- Matthew D Daugherty
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.,Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Aaron M Schaller
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Adam P Geballe
- Divisions of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, United States.,Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, United States.,Department of Microbiology, University of Washington School of Medicine, Seattle, United States.,Department of Medicine, University of Washington School of Medicine, Seattle, United States
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.,Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, United States
| |
Collapse
|
18
|
Brennan G, Kitzman JO, Shendure J, Geballe AP. Evasion of the African green monkey protein kinase R pathway by mutation of vaccinia virus RNA polymerase. The Journal of Immunology 2016. [DOI: 10.4049/jimmunol.196.supp.217.27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
One of the earliest barriers to cross-species transmission is mediated by host restriction factors, a group of antiviral proteins that have evolved to detect and then inhibit viral replication. To productively infect a new species, viruses must rapidly adapt to overcome host-specific orthologs of these restriction factors. To model this process we created a recombinant vaccinia virus (VACV), replacing its antagonists of the host restriction factor PKR with the rhesus cytomegalovirus PKR antagonist RhTRS1 (VACVΔEΔK+RhTRS1). Relative to wildtype virus, VACVΔEΔK+RhTRS1 replication was reduced 100-fold in primary African green monkey (AGM) fibroblasts. This replication defect was mediated entirely by PKR. After several rounds of serial passage, we found that genetic amplification of rhtrs1 rescued VACVΔEΔK+RhTRS1 replication in AGM cells. Further serial passage identified mutations in two VACV genes that were individually sufficient to rescue VACVΔEΔK+RhTRS1 replication in AGM cells. Fixation of these mutations coincided with collapse of the rhtrs1 amplification. One of these mutations occurred in the catalytic subunit of the viral RNA polymerase, A24R, and provided a replication benefit independent of rhtrs1. Different mutations in A24R have been shown to prevent activation of RNase L by reducing dsRNA production during viral infection. However, the A24R mutation that evolved during this serial passage does not prevent RNase L activation in AGM cells. Furthermore, this mutation does not decrease the total concentration of dsRNA produced during infection. This work identifies new PKR evasion genes, and suggests that the viral RNA polymerase is an important modulator of multiple host innate immune responses during infection.
Collapse
|
19
|
Braggin JE, Child SJ, Geballe AP. Essential role of protein kinase R antagonism by TRS1 in human cytomegalovirus replication. Virology 2015; 489:75-85. [PMID: 26716879 DOI: 10.1016/j.virol.2015.11.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Revised: 11/03/2015] [Accepted: 11/30/2015] [Indexed: 01/13/2023]
Abstract
Human cytomegalovirus (HCMV) lacking TRS1 and IRS1 (HCMV[ΔI/ΔT]) cannot replicate in cell culture. Although both proteins can block the protein kinase R (PKR) pathway, they have multiple other activities and binding partners. It remains unknown which functions are essential for HCMV replication. To investigate this issue, we first identified a TRS1 mutant that is unable to bind to PKR. Like HCMV[ΔI/ΔT], a recombinant HCMV containing this mutant (HCMV[TRS1-Mut 1]) did not replicate in wild-type cells. However, HCMV[ΔI/ΔT] did replicate in cells in which PKR expression was reduced by RNA interference. Moreover, HCMV[ΔI/ΔT] and HCMV[TRS1-Mut 1] replicated to similar levels as virus containing wild-type TRS1 in cell lines in which PKR expression was knocked out by CRISPR/Cas9-mediated genome editing. These results demonstrate that the sole essential function of TRS1 is to antagonize PKR and that its other activities do not substantially enhance HCMV replication, at least in cultured human fibroblasts.
Collapse
Affiliation(s)
- Jacquelyn E Braggin
- Department of Microbiology, University of Washington Seattle, WA 98115, United States; Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States.
| | - Stephanie J Child
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States.
| | - Adam P Geballe
- Department of Microbiology, University of Washington Seattle, WA 98115, United States; Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States; Department of Medicine, University of Washington, Seattle, WA 98115, United States.
| |
Collapse
|
20
|
Brennan G, Kitzman JO, Rothenburg S, Shendure J, Geballe AP. Adaptive gene amplification as an intermediate step in the expansion of virus host range. PLoS Pathog 2014; 10:e1004002. [PMID: 24626510 PMCID: PMC3953438 DOI: 10.1371/journal.ppat.1004002] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 02/01/2014] [Indexed: 12/02/2022] Open
Abstract
The majority of recently emerging infectious diseases in humans is due to cross-species pathogen transmissions from animals. To establish a productive infection in new host species, viruses must overcome barriers to replication mediated by diverse and rapidly evolving host restriction factors such as protein kinase R (PKR). Many viral antagonists of these restriction factors are species specific. For example, the rhesus cytomegalovirus PKR antagonist, RhTRS1, inhibits PKR in some African green monkey (AGM) cells, but does not inhibit human or rhesus macaque PKR. To model the evolutionary changes necessary for cross-species transmission, we generated a recombinant vaccinia virus that expresses RhTRS1 in a strain that lacks PKR inhibitors E3L and K3L (VVΔEΔK+RhTRS1). Serially passaging VVΔEΔK+RhTRS1 in minimally-permissive AGM cells increased viral replication 10- to 100-fold. Notably, adaptation in these AGM cells also improved virus replication 1000- to 10,000-fold in human and rhesus cells. Genetic analyses including deep sequencing revealed amplification of the rhtrs1 locus in the adapted viruses. Supplying additional rhtrs1 in trans confirmed that amplification alone was sufficient to improve VVΔEΔK+RhTRS1 replication. Viruses with amplified rhtrs1 completely blocked AGM PKR, but only partially blocked human PKR, consistent with the replication properties of these viruses in AGM and human cells. Finally, in contrast to AGM-adapted viruses, which could be serially propagated in human cells, VVΔEΔK+RhTRS1 yielded no progeny virus after only three passages in human cells. Thus, rhtrs1 amplification in a minimally permissive intermediate host was a necessary step, enabling expansion of the virus range to previously nonpermissive hosts. These data support the hypothesis that amplification of a weak viral antagonist may be a general evolutionary mechanism to permit replication in otherwise resistant host species, providing a molecular foothold that could enable further adaptations necessary for efficient replication in the new host. The spread of microbes from animals to humans has been responsible for most recently emerging human infectious diseases, including AIDS, bird flu, and SARS. Therefore, understanding the evolutionary and molecular mechanisms underlying cross-species transmission is of critical importance for public health. After entering a new host cell, the success of a virus depends on its ability to overcome antiviral factors in the cell, such as protein kinase R (PKR). To investigate the process of virus transmission between species, we employed a recombinant vaccinia virus (VVΔEΔK+RhTRS1) expressing the rhesus cytomegalovirus PKR antagonist RhTRS1. This protein inhibits some African green monkey (AGM) PKRs; however, it does not inhibit human or rhesus variants of PKR. Serial passaging VVΔEΔK+RhTRS1 in RhTRS1-resistant AGM cells resulted in rhtrs1 duplication in the viral genome, which improved VVΔEΔK+RhTRS1 replication in AGM cells. Remarkably, rhtrs1 duplication also enhanced virus replication in human and rhesus cells. In contrast, passage of VVΔEΔK+RhTRS1 in human cells, without prior adaptation in AGM cells, did not improve VVΔEΔK+RhTRS1 replication. These results support the hypothesis that amplification of a weak viral antagonist of a host defense protein in one species may enable cross-species transmission into new hosts that are nonpermissive to the initial virus.
Collapse
Affiliation(s)
- Greg Brennan
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Jacob O. Kitzman
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Stefan Rothenburg
- Division of Biology, Kansas State University, Manhattan, Kansas, United States of America
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Adam P. Geballe
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Departments of Microbiology and Medicine, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| |
Collapse
|
21
|
Bierle CJ, Semmens KM, Geballe AP. Double-stranded RNA binding by the human cytomegalovirus PKR antagonist TRS1. Virology 2013; 442:28-37. [PMID: 23601785 DOI: 10.1016/j.virol.2013.03.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 02/15/2013] [Accepted: 03/25/2013] [Indexed: 02/02/2023]
Abstract
Protein Kinase R (PKR) inhibits translation initiation following double-stranded RNA (dsRNA) binding and thereby represses viral replication. Human cytomegalovirus (HCMV) encodes two noncanonical dsRNA binding proteins, IRS1 and TRS1, and the expression of at least one of these PKR antagonists is essential for HCMV replication. In this study, we investigated the role of dsRNA binding by TRS1 in PKR inhibition. We found that purified TRS1 binds specifically to dsRNA with an affinity lower than that of PKR. Point mutants in the TRS1 dsRNA binding domain that were deficient in rescuing the replication of vaccinia virus lacking its PKR antagonist E3L were unable to bind to dsRNA but retained the ability bind to PKR. Thus TRS1 binding to dsRNA and to PKR are separable. Overall, our results are most consistent with a model in which TRS1 binds simultaneously to both dsRNA and PKR to inhibit PKR activation.
Collapse
Affiliation(s)
- Craig J Bierle
- Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98115, United States.
| | | | | |
Collapse
|
22
|
Elde NC, Child SJ, Eickbush MT, Kitzman JO, Rogers KS, Shendure J, Geballe AP, Malik HS. Poxviruses deploy genomic accordions to adapt rapidly against host antiviral defenses. Cell 2012; 150:831-41. [PMID: 22901812 DOI: 10.1016/j.cell.2012.05.049] [Citation(s) in RCA: 225] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 05/29/2012] [Accepted: 05/30/2012] [Indexed: 12/17/2022]
Abstract
In contrast to RNA viruses, double-stranded DNA viruses have low mutation rates yet must still adapt rapidly in response to changing host defenses. To determine mechanisms of adaptation, we subjected the model poxvirus vaccinia to serial propagation in human cells, where its antihost factor K3L is maladapted against the antiviral protein kinase R (PKR). Viruses rapidly acquired higher fitness via recurrent K3L gene amplifications, incurring up to 7%-10% increases in genome size. These transient gene expansions were necessary and sufficient to counteract human PKR and facilitated the gain of an adaptive amino acid substitution in K3L that also defeats PKR. Subsequent reductions in gene amplifications offset the costs associated with larger genome size while retaining adaptive substitutions. Our discovery of viral "gene-accordions" explains how poxviruses can rapidly adapt to defeat different host defenses despite low mutation rates and reveals how classical Red Queen conflicts can progress through unrecognized intermediates.
Collapse
Affiliation(s)
- Nels C Elde
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Bierle CJ, Schleiss MR, Geballe AP. Antagonism of the protein kinase R pathway by the guinea pig cytomegalovirus US22-family gene gp145. Virology 2012; 433:157-66. [PMID: 22917493 DOI: 10.1016/j.virol.2012.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 05/11/2012] [Accepted: 08/01/2012] [Indexed: 01/17/2023]
Abstract
Viral double-stranded RNA (dsRNA) activates protein kinase R (PKR), which phosphorylates eIF2α and inhibits translation. In response, viruses have evolved various strategies to evade the antiviral impact of PKR. We investigated whether guinea pig cytomegalovirus (GPCMV), a useful model of congenital CMV infection, encodes a gene that interferes with the PKR pathway. Using a proteomic screen, we identified several GPCMV dsRNA-binding proteins, among which only gp145 rescued replication of a vaccinia virus mutant that lacks E3L. gp145 also reversed the inhibitory effects of PKR on expression of a cotransfected reporter gene. Mapping studies demonstrated that the gp145 dsRNA-binding domain has homology to the PKR antagonists of other CMVs. However, dsRNA-binding by gp145 is not sufficient for it to block PKR. gp145 differs from the PKR antagonists of murine CMV in that it functions alone and from those encoded by human CMV in functioning in cells from both primates and rodents.
Collapse
Affiliation(s)
- Craig J Bierle
- Program in Molecular and Cellular Biology, University of Washington, Seattle, WA 98115, United States.
| | | | | |
Collapse
|
24
|
Abstract
Human cytomegalovirus (CMV), one of the eight herpesviruses that commonly infect humans, is best known for its propensity to cause disease in immunocompromised patients, especially transplant recipients, patients with advanced AIDS, and congenitally infected newborns. Advances in molecular virology coupled with improvements in diagnostic methods and treatment options have vastly improved our understanding of and ability to manage CMV, but many uncertainties remain, including the mechanisms of persistence and pathogenesis and its hypothesized roles in a variety of human illnesses. Here we review recent advances that are reshaping our view and approach to this fascinating virus.
Collapse
Affiliation(s)
- Michael Boeckh
- Division of Vaccine and Infectious Disease and
Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Medicine, University of Washington, Seattle, Washington, USA.
Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Adam P. Geballe
- Division of Vaccine and Infectious Disease and
Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Medicine, University of Washington, Seattle, Washington, USA.
Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.
Department of Microbiology, University of Washington, Seattle, Washington, USA
| |
Collapse
|
25
|
Abstract
Multiple proteins interacting with DNA polymerases orchestrate DNA replication. Human cytomegalovirus (HCMV) encodes a DNA polymerase that includes the presumptive processivity factor UL44. UL44 is structurally homologous to the eukaryotic DNA polymerase processivity factor proliferating cell nuclear antigen (PCNA), which interacts with numerous proteins. Previous proteomic analysis has identified the HCMV protein IRS1 as a candidate protein interacting with UL44. Nuclease-resistant reciprocal co-immunoprecipitation of UL44 with IRS1 and with TRS1, which has an amino terminus identical to that of IRS1, was observed from lysate of cells infected with viruses expressing epitope-tagged UL44, epitope-tagged IRS1 or epitope-tagged TRS1. Western blotting of protein immunoprecipitated from infected cell lysate indicated that epitope-tagged IRS1 and TRS1 do not associate simultaneously with UL44. Glutathione S-transferase pull-down experiments indicated that IRS1 and TRS1 interact with UL44 via a region that is identical in both proteins. Taken together, these data suggest that IRS1 and TRS1 may compete for association with UL44 and may affect UL44 function differentially.
Collapse
Affiliation(s)
- Blair L Strang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | | | | |
Collapse
|
26
|
Abstract
Human cytomegalovirus (HCMV), which infects the majority of the population worldwide, causes few, if any, symptoms in otherwise healthy people but is responsible for considerable morbidity and mortality in immunocompromised patients and in congenitally infected newborns. The evolutionary success of HCMV depends in part on its ability to evade host defense systems. Here we review recent progress in elucidating the remarkable assortment of mechanisms employed by HCMV and the related beta-herpesviruses, murine cytomegaloviruses (MCMV) and rhesus cytomegaloviruses (RhCMV), for counteracting the host interferon (IFN) response. Very early after infection, cellular membrane sensors such as the lymphotoxin beta receptor initiate the production of antiviral cytokines including type I IFNs. However, virion factors, such as pp65 (ppUL83) and viral proteins made soon after infection including the immediate early gene 2 protein (pUL122), repress this response by interfering with steps in the activation of IFN regulatory factor 3 and NF-kappaB. CMVs then exert a multi-pronged attack on downstream IFN signaling. HCMV infection results in decreased accumulation and phosphorylation of the IFN signaling kinases Jak1 and Stat2, and the MCMV protein pM27 mediates Stat2 down-regulation, blocking both type I and type II IFN signaling. The HCMV immediate early gene 1 protein (pUL123) interacts with Stat2 and inhibits transcriptional activation of IFN-regulated genes. Infection also causes reduction in the abundance of p48/IRF9, a component of the ISGF3 transcription factor complex. Furthermore, CMVs have multiple genes involved in blocking the function of IFN-induced effectors. For example, viral double-stranded RNA-binding proteins are required to prevent the shutoff of protein synthesis by protein kinase R, further demonstrating the vital importance of evading the IFN response at multiple levels during infection.
Collapse
Affiliation(s)
- Emily E Marshall
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
| | | |
Collapse
|
27
|
Elde NC, Child SJ, Geballe AP, Malik HS. Protein kinase R reveals an evolutionary model for defeating viral mimicry. Nature 2008; 457:485-9. [PMID: 19043403 PMCID: PMC2629804 DOI: 10.1038/nature07529] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Accepted: 10/08/2008] [Indexed: 01/22/2023]
Abstract
Distinguishing self from non-self is a fundamental biological challenge. Many pathogens exploit the challenge of self discrimination by employing mimicry to subvert key cellular processes including the cell cycle, apoptosis, and cytoskeletal dynamics1-5. Other mimics interfere with immunity6, 7. Poxviruses encode K3L, a mimic of eIF2α, which is the substrate of Protein Kinase R (PKR), an important component of innate immunity in vertebrates8, 9. The PKR-K3L interaction exemplifies the conundrum imposed by viral mimicry. To be effective, PKR must recognize a conserved substrate (eIF2α) while avoiding rapidly evolving substrate mimics like K3L. Using the PKR-K3L system and a combination of phylogenetic and functional analyses, we uncover evolutionary strategies by which host proteins can overcome mimicry. We find that PKR has evolved under dramatic episodes of positive selection in primates. The ability of PKR to evade viral mimics is partly due to positive selection at sites most intimately involved in eIF2α recognition. We also find that adaptive changes on multiple surfaces of PKR produce combinations of substitutions that increase the odds of defeating mimicry. Thus, while it can appear that pathogens gain insurmountable advantages by mimicking cellular components, host factors like PKR can compete in molecular ‘arms races’ with mimics because of remarkable evolutionary flexibility at protein interaction interfaces challenged by mimicry.
Collapse
Affiliation(s)
- Nels C Elde
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | | | | | | |
Collapse
|
28
|
Hakki M, Geballe AP. Cellular serine/threonine phosphatase activity during human cytomegalovirus infection. Virology 2008; 380:255-63. [PMID: 18757073 DOI: 10.1016/j.virol.2008.07.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 06/05/2008] [Accepted: 07/24/2008] [Indexed: 11/16/2022]
Abstract
While the importance of cellular and viral kinases in HCMV replication has been demonstrated, relatively little is known about the activity of cellular phosphatases. We conducted a series of experiments designed to investigate the effect of HCMV infection on cellular serine/threonine phosphatase activity. We found that the abundance of two major cellular serine/threonine phosphatases, PP1 and PP2A, increases during HCMV infection. This was associated with an increase in threonine phosphatase activity in HCMV-infected cells. HCMV infection conferred resistance to the effects of the phosphatase inhibitors calyculin A (CA) and okadaic acid with regards to global protein hyperphosphorylation and the shutoff of protein synthesis. The protective effect of HCMV infection could be overcome at a high concentration of CA, suggesting that cellular phosphatase activity is required for critical cellular processes during HCMV infection. Specifically, phosphatase activity was required to limit the accumulation of phospho-eIF2alpha, but not phospho-PKR, during HCMV infection.
Collapse
Affiliation(s)
- Morgan Hakki
- Divisions of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
| | | |
Collapse
|
29
|
Spevak CC, Park EH, Geballe AP, Pelletier J, Sachs MS. her-2 upstream open reading frame effects on the use of downstream initiation codons. Biochem Biophys Res Commun 2006; 350:834-41. [PMID: 17045969 PMCID: PMC1668710 DOI: 10.1016/j.bbrc.2006.09.128] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 09/11/2006] [Indexed: 11/30/2022]
Abstract
The her-2 (neu, erbB-2) oncogene encodes a 185-kDa transmembrane receptor tyrosine kinase. HER2 overexpression occurs in numerous primary human tumors and contributes to 25-30% of breast and ovarian carcinomas. Synthesis of HER2 is controlled in part by an upstream open reading frame (uORF) present in the transcript. We used synthetic capped and polyadenylated mRNAs containing sequences derived from the 5' region of the her-2 transcript fused to a firefly luciferase (LUC) reporter to examine this uORF's effect on translation in cell-free systems derived from reticulocytes, wheat germ and Neurospora crassa, and in RNA-transfected HeLa cells. The uORF reduced translation of the downstream cistron in all systems. [(35)S]Met labeling of in vitro translation products obtained indicated that the uORF also affected downstream start-site selection. Primer extension inhibition (toeprint) assays of ribosomes loaded at initiation codons in reticulocyte lysates indicated that the uORF affected the interaction of ribosomes with the primary her-2 AUG codon.
Collapse
Affiliation(s)
- Christina C. Spevak
- Department of Environmental & Biomolecular Systems,
Oregon Health and Science University, Beaverton, OR 97006
| | - Eun-Hee Park
- Department of Biochemistry and McGill Cancer Center, McGill
University, Montreal, Quebec H3G 1Y6
| | - Adam P. Geballe
- Divisions of Human Biology and Clinical Research, C2-023, Fred
Hutchinson Cancer Research Center, Seattle, Washington 98109; Departments of
Medicine and Microbiology University of Washington, Seattle, WA 98115
| | - Jerry Pelletier
- Department of Biochemistry and McGill Cancer Center, McGill
University, Montreal, Quebec H3G 1Y6
- McGill Cancer Center, McGill University, Montreal, Quebec H3G
1Y6
| | - Matthew S. Sachs
- Department of Environmental & Biomolecular Systems,
Oregon Health and Science University, Beaverton, OR 97006
- Department of Molecular Microbiology and Immunology, Oregon
Health & Science University, Portland, Oregon 97201
- Address correspondence to: Matthew S. Sachs, Department of
Environmental and Biomolecular Systems, Oregon Health & Science
University, 20000 NW Walker Road, Beaverton OR, 97006-8921, Tel. 503-748-1487;
Fax 214 648-6899; E-mail
| |
Collapse
|
30
|
Child SJ, Hanson LK, Brown CE, Janzen DM, Geballe AP. Double-stranded RNA binding by a heterodimeric complex of murine cytomegalovirus m142 and m143 proteins. J Virol 2006; 80:10173-80. [PMID: 17005694 PMCID: PMC1617283 DOI: 10.1128/jvi.00905-06] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 07/12/2006] [Indexed: 11/20/2022] Open
Abstract
In response to viral infection, cells activate a variety of antiviral responses, including several that are triggered by double-stranded (ds) RNA. Among these are the protein kinase R and oligoadenylate synthetase/RNase L pathways, both of which result in the shutoff of protein synthesis. Many viruses, including human cytomegalovirus, encode dsRNA-binding proteins that prevent the activation of these pathways and thereby enable continued protein synthesis and viral replication. We have extended these analyses to another member of the beta subfamily of herpesviruses, murine cytomegalovirus (MCMV), and now report that products of the m142 and m143 genes together bind dsRNA. Coimmunoprecipitation experiments demonstrate that these two proteins interact in infected cells, consistent with their previously reported colocalization. Jointly, but not individually, the proteins rescue replication of a vaccinia virus mutant with a deletion of the dsRNA-binding protein gene E3L (VVDeltaE3L). Like the human cytomegalovirus dsRNA-binding protein genes TRS1 and IRS1, m142 and m143 are members of the US22 gene family. We also found that two other members of the MCMV US22 family, M23 and M24, encode dsRNA-binding proteins, but they do not rescue VVDeltaE3L replication. These results reveal that MCMV, like many other viruses, encodes dsRNA-binding proteins, at least two of which can inhibit dsRNA-activated antiviral pathways. However, unlike other well-studied examples, the MCMV proteins appear to act in a heterodimeric complex.
Collapse
Affiliation(s)
- Stephanie J Child
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, MS C2-023, Seattle, WA 98109-1024, USA
| | | | | | | | | |
Collapse
|
31
|
Abstract
The human cytomegalovirus (HCMV) TRS1 and IRS1 genes block the phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2alpha) and the consequent shutoff of cellular protein synthesis that occur during infection with vaccinia virus (VV) deleted of the double-stranded RNA binding protein gene E3L (VVDeltaE3L). To further define the underlying mechanism, we first evaluated the effect of pTRS1 on protein kinase R (PKR), the double-stranded RNA (dsRNA)-dependent eIF2alpha kinase. Immunoblot analyses revealed that pTRS1 expression in the context of a VVDeltaE3L recombinant decreased levels of PKR in the cytoplasm and increased its levels in the nucleus of infected cells, an effect not seen with wild-type VV or a VVDeltaE3L recombinant virus expressing E3L. This effect of pTRS1 was confirmed by visualizing the nuclear relocalization of PKR-EGFP expressed by transient transfection. PKR present in both the nuclear and cytoplasmic fractions was nonphosphorylated, indicating that it was unactivated when TRS1 was present. PKR also accumulated in the nucleus during HCMV infection as determined by indirect immunofluorescence and immunoblot analysis. Binding assays revealed that pTRS1 interacted with PKR in mammalian cells and in vitro. This interaction required the same carboxy-terminal region of pTRS1 that is necessary to rescue VVDeltaE3L replication in HeLa cells. The carboxy terminus of pIRS1 was also required for rescue of VVDeltaE3L and for mediating an interaction of pIRS1 with PKR. These results suggest that these HCMV genes directly interact with PKR and inhibit its activation by sequestering it in the nucleus, away from both its activator, cytoplasmic dsRNA, and its substrate, eIF2alpha.
Collapse
Affiliation(s)
- Morgan Hakki
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109, USA
| | | | | | | |
Collapse
|
32
|
Affiliation(s)
- Matthew S Sachs
- Department of Environmental and Biomolecular Systems, Oregon Health and Science University, Beaverton, Oregon 97006, USA.
| | | |
Collapse
|
33
|
Abstract
The human cytomegalovirus (HCMV) TRS1 and IRS1 genes rescue replication of vaccinia virus (VV) that has a deletion of the double-stranded RNA binding protein gene E3L (VVDeltaE3L). Like E3L, these HCMV genes block the activation of key interferon-induced, double-stranded RNA (dsRNA)-activated antiviral pathways. We investigated the hypothesis that the products of these HCMV genes act by binding to dsRNA. pTRS1 expressed by cell-free translation or by infection of mammalian cells with HCMV or recombinant VV bound to dsRNA. Competition experiments revealed that pTRS1 preferentially bound to dsRNA compared to double-stranded DNA or single-stranded RNA. 5'- and 3'-end deletion analyses mapped the TRS1 dsRNA-binding domain to amino acids 74 through 248, a region of identity to pIRS1 that contains no homology to known dsRNA-binding proteins. Deletion of the majority of this region (Delta86-246) completely abrogated dsRNA binding. To determine the role of the dsRNA-binding domain in the rescue of VVDeltaE3L replication, wild-type or deletion mutants of TRS1 were transfected into HeLa cells, which were then infected with VVDeltaE3L. While full-length TRS1 rescued VVDeltaE3L replication, deletion mutants affecting a carboxy-terminal region of TRS1 that is not required for dsRNA binding failed to rescue VVDeltaE3L. Analyses of stable cell lines revealed that the carboxy-terminal domain is necessary to prevent the shutoff of protein synthesis and the phosphorylation of eIF2alpha after VVDeltaE3L infection. Thus, pTRS1 contains an unconventional dsRNA-binding domain at its amino terminus, but a second function involving the carboxy terminus is also required for countering host cell antiviral responses.
Collapse
Affiliation(s)
- Morgan Hakki
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N, MS C2-023, Seattle, WA 98109-1024, USA
| | | |
Collapse
|
34
|
Scott JD, Englund JA, Myerson D, Geballe AP. Influenza A pneumonia presenting as progressive focal infiltrates in a stem cell transplant recipient. J Clin Virol 2004; 31:96-9. [PMID: 15364264 DOI: 10.1016/j.jcv.2004.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/27/2004] [Accepted: 05/18/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND Stem cell transplant recipients are susceptible to pulmonary infections, including influenza A. Typically, isolated influenza pneumonia has a diffuse, interstitial infiltrate pattern. OBJECTIVES To describe the unusual clinical and radiographic course of influenza A pneumonia in a stem cell transplant recipient. STUDY DESIGN Case report in which microbiologic assays, bronchoscopic and pathologic specimens are obtained. RESULTS We describe a patient with influenza A pneumonia 8 months following a peripheral blood stem cell transplant who presented with minimal respiratory symptoms and rapidly progressing, focal pulmonary infiltrates. The large size and appearance of the masses have not been reported before in a patient with isolated influenza. CONCLUSION This case highlights the differences of presentation and importance of early diagnosis and treatment of immunocompromised patients infected with influenza.
Collapse
Affiliation(s)
- John D Scott
- Department of Medicine, University of Washington, Harborview Medical Center, 325 Ninth Avenue, Box 359938, Seattle, WA 98104-2499, USA.
| | | | | | | |
Collapse
|
35
|
Abstract
Two competing events, termination and readthrough (or nonsense suppression), can occur when a stop codon reaches the A-site of a translating ribosome. Translation termination results in hydrolysis of the final peptidyl-tRNA bond and release of the completed nascent polypeptide. Alternatively, readthrough, in which the stop codon is erroneously decoded by a suppressor or near cognate transfer RNA (tRNA), results in translation past the stop codon and production of a protein with a C-terminal extension. The relative frequency of termination versus readthrough is determined by parameters such as the stop codon nucleotide context, the activities of termination factors and the abundance of suppressor tRNAs. Using a sensitive and versatile readthrough assay in conjunction with RNA interference technology, we assessed the effects of depleting eukaryotic releases factors 1 and 3 (eRF1 and eRF3) on the termination reaction in human cell lines. Consistent with the established role of eRF1 in triggering peptidyl-tRNA hydrolysis, we found that depletion of eRF1 enhances readthrough at all three stop codons in 293 cells and HeLa cells. The role of eRF3 in eukarytotic translation termination is less well understood as its overexpression has been shown to have anti-suppressor effects in yeast but not mammalian systems. We found that depletion of eRF3 has little or no effect on readthrough in 293 cells but does increase readthrough at all three stop codons in HeLa cells. These results support a direct role for eRF3 in translation termination in higher eukaryotes and also highlight the potential for differences in the abundance or activity of termination factors to modulate the balance of termination to readthrough reactions in a cell-type-specific manner.
Collapse
Affiliation(s)
- Deanna M Janzen
- Division of Human Biology, Fred Hutchinson Cancer Research Center, PO Box 19024, 1100 Fairview Avenue North-C2-023, Seattle, WA 98109-1024, USA
| | | |
Collapse
|
36
|
Abstract
During infection with human cytomegalovirus (HCMV), cellular protein synthesis continues even as viral proteins are being synthesized in abundance. Thus, HCMV may have a mechanism for counteracting host cell antiviral pathways that act by shutting off translation. Consistent with this view, HCMV infection of human fibroblasts rescues the replication of a vaccinia virus mutant lacking the double-stranded RNA-binding protein gene E3L (VVdeltaE3L). HCMV also prevents the phosphorylation of the eukaryotic translation initiation factor eIF-2alpha, the activation of RNase L, and the shutoff of viral and cellular protein synthesis that otherwise result from VVdeltaE3L infection. To identify the HCMV gene(s) responsible for these effects, we prepared a library of VVdeltaE3L recombinants containing HCMV genomic fragments. By infecting nonpermissive cells with this library and screening for VV gene expression and replication, we isolated a virus containing a 2.8-kb HCMV fragment that rescues replication of VVdeltaE3L. The fragment comprises the 3' end of the J1S open reading frame through the entire TRS1 gene. Analyses of additional VVdeltaE3L recombinants revealed that the protein encoded by TRS1, pTRS1, as well as the closely related IRS1 gene, rescues VVdeltaE3L replication and prevent the shutoff of protein synthesis, the phosphorylation of eIF-2alpha, and activation of RNase L. These results demonstrate that TRS1 and IRS1 are able to counteract critical host cell antiviral response pathways.
Collapse
Affiliation(s)
- Stephanie J Child
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
| | | | | | | |
Collapse
|
37
|
Affiliation(s)
- D M Janzen
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Departments of Medicine and Microbiology, University of Washington, Seattle, Washington, USA
| | | |
Collapse
|
38
|
Janzen DM, Frolova L, Geballe AP. Inhibition of translation termination mediated by an interaction of eukaryotic release factor 1 with a nascent peptidyl-tRNA. Mol Cell Biol 2002; 22:8562-70. [PMID: 12446775 PMCID: PMC139875 DOI: 10.1128/mcb.22.24.8562-8570.2002] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Expression of the human cytomegalovirus UL4 gene is inhibited by translation of a 22-codon-upstream open reading frame (uORF2). The peptide product of uORF2 acts in a sequence-dependent manner to inhibit its own translation termination, resulting in persistence of the uORF2 peptidyl-tRNA linkage. Consequently, ribosomes stall at the uORF2 termination codon and obstruct downstream translation. Since termination appears to be the critical step affected by translation of uORF2, we examined the role of eukaryotic release factors 1 and 3 (eRF1 and eRF3) in the inhibitory mechanism. In support of the hypothesis that an interaction between eRF1 and uORF2 contributes to uORF2 inhibitory activity, specific residues in each protein, glycines 183 and 184 of the eRF1 GGQ motif and prolines 21 and 22 of the uORF2 peptide, were found to be necessary for full inhibition of downstream translation. Immunoblot analyses revealed that eRF1, but not eRF3, accumulated in the uORF2-stalled ribosome complex. Finally, increased puromycin sensitivity was observed after depletion of eRF1 from the stalled ribosome complex, consistent with inhibition of peptidyl-tRNA hydrolysis resulting from an eRF1-uORF2 peptidyl-tRNA interaction. These results reveal the paradoxical potential for interactions between a nascent peptide and eRF1 to obstruct the translation termination cascade.
Collapse
Affiliation(s)
- Deanna M Janzen
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | | | | |
Collapse
|
39
|
MESH Headings
- Bacterial Proteins/biosynthesis
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Chloramphenicol/pharmacology
- Erythromycin/pharmacology
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Escherichia coli Proteins
- Gene Expression Regulation, Bacterial
- Peptide Chain Termination, Translational
- Peptidyl Transferases/antagonists & inhibitors
- Peptidyl Transferases/metabolism
- Protein Biosynthesis
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Ribosomal/metabolism
- RNA, Transfer/metabolism
- RNA, Transfer, Amino Acyl/metabolism
- Ribosomes/metabolism
- Tryptophan/metabolism
- Tryptophanase/biosynthesis
- Tryptophanase/genetics
Collapse
Affiliation(s)
- Matthew S Sachs
- Department of Biochemistry and Molecular Biology, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, OR 97006, USA.
| | | |
Collapse
|
40
|
Randolph-Habecker J, Iwata M, Geballe AP, Jarrahian S, Torok-Storb B. Interleukin-1-mediated inhibition of cytomegalovirus replication is due to increased IFN-beta production. J Interferon Cytokine Res 2002; 22:765-72. [PMID: 12184914 DOI: 10.1089/107999002320271350] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous studies have demonstrated that the intercellular spread of cytomegalovirus (CMV) is reduced in marrow stromal cells that either secrete interleukin-1 (IL-1) or are treated with exogenous IL-1. Here, we report that IL-1-treated marrow stromal cells and fibroblasts, when infected with CMV, produce decreased amounts of infectious progeny virus. CMV-infected cells treated with IL-1 contained more interferon-beta (IFN-beta) mRNA at 24 h postinfection compared with untreated, infected cells. IFN-beta protein secreted into fibroblast culture supernatants increased from 46 +/- 1 IU/ml in untreated, infected cells to 116 +/- 5 IU/ml in IL-1-treated infected cells. When IFN-beta activity was inhibited, using blocking antibodies to either the cytokine or the IFN-alpha/beta receptor, the addition of IL-1 no longer limited viral spread. Furthermore, viral spread in nonIL-1-treated cultures was inhibited by the addition of recombinant IFN-beta. These studies suggest that IL-1 functions to limit CMV spread by increasing the expression of IFN-beta, which in turn reduces production of infectious virus.
Collapse
|
41
|
Child SJ, Jarrahian S, Harper VM, Geballe AP. Complementation of vaccinia virus lacking the double-stranded RNA-binding protein gene E3L by human cytomegalovirus. J Virol 2002; 76:4912-8. [PMID: 11967308 PMCID: PMC136161 DOI: 10.1128/jvi.76.10.4912-4918.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cellular response to viral infection often includes activation of pathways that shut off protein synthesis and thereby inhibit viral replication. In order to enable efficient replication, many viruses carry genes such as the E3L gene of vaccinia virus that counteract these host antiviral pathways. Vaccinia virus from which the E3L gene has been deleted (VVDeltaE3L) is highly sensitive to interferon and exhibits a restricted host range, replicating very inefficiently in many cell types, including human fibroblast and U373MG cells. To determine whether human cytomegalovirus (CMV) has a mechanism for preventing translational shutoff, we evaluated the ability of CMV to complement the deficiencies in replication and protein synthesis associated with VVDeltaE3L. CMV, but not UV-inactivated CMV, rescued VVDeltaE3L late gene expression and replication. Thus, complementation of the VVDeltaE3L defect appears to depend on de novo CMV gene expression and is not likely a result of CMV binding to the cell receptor or of a virion structural protein. CMV rescued VVDeltaE3L late gene expression even in the presence of ganciclovir, indicating that CMV late gene expression is not required for complementation of VVDeltaE3L. The striking decrease in overall translation after infection with VVDeltaE3L was prevented by prior infection with CMV. Finally, CMV blocked both the induction of eukaryotic initiation factor 2alpha (eIF2alpha) phosphorylation and activation of RNase L by VVDeltaE3L. These results suggest that CMV has one or more immediate-early or early genes that ensure maintenance of a high protein synthetic capacity during infection by preventing activation of the PKR/eIF2alpha phosphorylation and 2-5A oligoadenylate synthetase/RNase L pathways.
Collapse
Affiliation(s)
- Stephanie J Child
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
| | | | | | | |
Collapse
|
42
|
Abstract
The human cytomegalovirus UL4 gene encodes a 48-kDa glycoprotein, expression of which is repressed at the translational level by a short upstream open reading frame (uORF2) within the UL4 transcript leader. Mutation of the uORF2 initiation codon in the viral genome eliminates ribosomal stalling at the uORF2 termination site, resulting in early and abundant gpUL4 protein synthesis. This mutation does not appear to affect viral replication kinetics in human fibroblasts. These results reveal that the unusual uORF2 inhibitory mechanism is a principal determinant of the abundance and timing of gpUL4 expression but is nonessential for replication in cell culture.
Collapse
Affiliation(s)
- J P Alderete
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | | | | |
Collapse
|
43
|
Bar M, Shannon-Lowe C, Geballe AP. Differentiation of human cytomegalovirus genotypes in immunocompromised patients on the basis of UL4 gene polymorphisms. J Infect Dis 2001; 183:218-225. [PMID: 11110652 DOI: 10.1086/317939] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2000] [Revised: 09/28/2000] [Indexed: 11/03/2022] Open
Abstract
The variety of clinical manifestations of human cytomegalovirus infection probably results from both viral and host factors. Because genetic markers that span the viral genome are needed to identify such viral factors, polymorphisms at the UL4 gene locus were analyzed. DNA sequence analyses revealed 4 UL4-based genotypes, 2 of which were closely related but distinguishable by an uncommon polymorphism that results in overexpression of gpUL4. Similarities in the spectra of polymorphisms detected in various sets of samples reveal that all UL4 types infect a diversity of organs in different patient groups and in different geographic locales. Simultaneous infection by >1 UL4 type is common in AIDS patients. Data from sequencing analyses and from a rapid and simple UL4 typing assay did not detect linkage between UL4 and glycoprotein B types, which suggests that UL4 genotyping should be useful for studies that attempt to identify cytomegalovirus genes involved in disease pathogenesis.
Collapse
Affiliation(s)
- M Bar
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | | | | |
Collapse
|
44
|
Affiliation(s)
- D R Morris
- Departments of Biochemistry, University of Washington, Seattle, USA.
| | | |
Collapse
|
45
|
Landini MP, Lazzarotto T, Xu J, Geballe AP, Mocarski ES. Humoral immune response to proteins of human cytomegalovirus latency-associated transcripts. Biol Blood Marrow Transplant 2000; 6:100-8. [PMID: 10741618 DOI: 10.1016/s1083-8791(00)70072-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Latent human cytomegalovirus (CMV) infection of hematopoietic progenitor cells is associated with the presence of latency-associated transcripts that may express 6 proteins larger than 44 amino acids in size (open reading frame [ORF] 55, ORF45, ORF94, ORF59, ORF154, ORF152/UL124). The serologic response to these proteins was evaluated in healthy seropositive individuals as well as in individuals undergoing active CMV infection. Individual recombinant GST-fusion proteins, prepared from bacteria, were found by enzyme-linked immunosorbent assay to be recognized by between 8% and 44% long-term healthy seropositive individuals, with ORF94 and ORF55 being the most broadly and significantly recognized. Although nearly all of serum samples (85%) recognized at least 1 of these proteins, none reacted with all 6. Patterns of antibody prevalence to these proteins in long-term seropositive individuals were similar to many antigens expressed during productive replication (IE1, ppUL57, ppUL83/pp65), but none were broadly detected by a majority of individuals, a characteristic of only a few productive-phase antigens, including ppUL44/ICP36 and ppUL32/pp150. Consistent with prevalence in long-term seropositive individuals, commercial preparations of pooled human gamma globulin were also found to recognize latency-associated proteins. Serologic reactivity to latency-associated proteins was slow to develop following primary infection, in a pattern distinct from any of the characterized replication-phase proteins tested here, and was boosted late after secondary infection or reactivation in solid-organ transplant recipients without showing a correlation with viremia or disease. These results provide evidence that proteins expressed from the latent region during natural infection exhibit immunogenicity comparable with most other characterized viral antigens, although the narrow response to individual latency-associated proteins likely precludes their use in serologic assays to investigate clinical correlates or outcome in transplant recipients.
Collapse
Affiliation(s)
- M P Landini
- Department of Clinical and Experimental Medicine, University of Bologna, Italy
| | | | | | | | | |
Collapse
|
46
|
Alderete JP, Jarrahian S, Geballe AP. Translational effects of mutations and polymorphisms in a repressive upstream open reading frame of the human cytomegalovirus UL4 gene. J Virol 1999; 73:8330-7. [PMID: 10482583 PMCID: PMC112850 DOI: 10.1128/jvi.73.10.8330-8337.1999] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human cytomegalovirus (HCMV) gpUL4 mRNA contains a 22-codon upstream open reading frame (uORF2), the peptide product of which represses downstream translation by blocking translation termination at its own stop codon and by causing ribosomes to stall on the mRNA. A distinctive feature of this unusual mechanism is its strict dependence on the uORF2 peptide sequence. To delineate sequence elements that function in the inhibitory mechanism, deletions and missense mutations affecting the previously uncharacterized amino-terminal region of uORF2 were analyzed in transient-transfection and infection assays. These experiments identified multiple codons in this region that are necessary for inhibition of downstream translation by uORF2 and, in conjunction with previous results, demonstrated that amino acids dispersed throughout the uORF2 peptide participate in the repressive mechanism. In contrast to the highly conserved carboxy terminus, the amino-terminal portion of the uORF2 peptide is polymorphic. A survey of uORF2 sequences in HCMV clinical isolates revealed that although most have uORF2 sequences that are predicted to retain the uORF2 inhibitory activity, approximately 15% contain polymorphisms at codons that are essential for full inhibition by uORF2. Consistent with predictions based on analyses of engineered mutations, two viral isolates with uORF2 sequences that do not inhibit downstream translation in transfection assays expressed much more gpUL4 protein but similar levels of UL4 mRNA compared to the levels produced by the prototypic laboratory strain HCMV (Towne) and another clinical isolate with an inhibitory variant uORF2. These results demonstrate that uORF2 is polymorphic in sequence and repressive activity and suggest that the uORF2 regulatory mechanism, although prevalent among natural HCMV isolates, is not absolutely essential for viral replication.
Collapse
Affiliation(s)
- J P Alderete
- Divisions of Human Biology and Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | | | | |
Collapse
|
47
|
Abstract
Overexpression of the HER-2 (neu, erbB-2) receptor results in cellular transformation and is associated with a variety of human cancers. Multiple mechanisms, including gene amplification and transcriptional, post-transcriptional, and translational controls contribute to the regulation of HER-2 expression. One of the components of these regulatory mechanisms is a short upstream open reading frame (uORF) in the HER-2 mRNA that represses downstream translation in a variety of cell types. Here we explore the mechanism by which this uORF exerts its inhibitory effect. As judged by comparisons of protein and mRNA abundance and by polysomal distribution analyses, the uORF represses translation of the HER-2 cistron or of a heterologous reporter gene. Despite its conservation among mammalian species, the peptide sequence of the uORF is not required for this inhibitory effect. Rather, the majority of ribosomes that load on the HER-2 mRNA most likely translate the uORF and are then unable to reinitiate at the downstream AUG codon, in part due to the short intercistronic spacing. A minority of ribosomes gain access to the HER-2 initiation codon either by leaky scanning past the upstream AUG codon or by reinitiating after having translated the uORF despite the short intercistronic region. These results suggest that the HER-2 uORF controls synthesis of this oncoprotein by limiting ribosomal access to downstream initiation sites.
Collapse
Affiliation(s)
- S J Child
- Divisions of Human Biology and Clinical Research, C2-023, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | | | | |
Collapse
|
48
|
Abstract
Overexpression of the HER-2 oncogene occurs in a variety of human tumors, including 25-30% of breast carcinomas, and has been associated with an adverse prognosis. Amplification of the HER-2 gene is frequently detected in tumors, but by itself may not fully account for HER-2 overexpression since transcriptional and post-transcriptional mechanisms also regulate HER-2 protein synthesis. Our studies reveal that the efficiency of HER-2 translation differs between primary and transformed cells. In primary human fibroblasts and human mammary epithelial cells, the HER-2 mRNA is associated with monosome and small polysome fractions. In contrast, in BT474 and MCF-7 human breast cancer cell lines and in COS-7 cells the mRNA co-sedimented with larger polysomes, indicating that it is more efficiently translated in these transformed cells. Northern analysis revealed no detectable mRNA size difference, and nuclease S1 protection and sequence analyses showed no differences between the HER-2 transcript leader in primary cells compared to transformed human cells. The transcript leader in all cell types contains a short upstream open reading frame that is also conserved in other mammalian species. Transient transfection assays revealed that the HER-2 transcript leader repressed downstream translation approximately five-fold in both primary and transformed cells and mutation of the upstream initiation codon alleviated most of the inhibitory effect. These results indicate that HER2 expression is translationally controlled both by a short upstream open reading frame that represses HER-2 translation in a cell type-independent manner, and by a distinct cell type-dependent mechanism that increases translational efficiency of HER-2 in transformed cells.
Collapse
Affiliation(s)
- S J Child
- Division of Molecular Medicine, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | | | | |
Collapse
|
49
|
Vieira J, Schall TJ, Corey L, Geballe AP. Functional analysis of the human cytomegalovirus US28 gene by insertion mutagenesis with the green fluorescent protein gene. J Virol 1998; 72:8158-65. [PMID: 9733857 PMCID: PMC110158 DOI: 10.1128/jvi.72.10.8158-8165.1998] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The protein encoded by the US28 gene of human cytomegalovirus (HCMV) has homology to G protein-coupled receptors (GCR). Previous studies demonstrated that recombinant US28 protein can bind the beta class of chemokines (K. Neote, D. DiGregorio, J. Y. Mak, R. Horuk, and T. J. Schall, Cell 72:415-425, 1993) and induce a rise in intracellular calcium after the binding of chemokines (J. L. Gao and P. M. Murphy, J. Biol. Chem. 269:28539-28542, 1994). In order to investigate the function of the US28 protein in virus-infected cells, a recombinant HCMV (HV5.8) was constructed, with the US28 open reading frame disrupted by the insertion of the Escherichia coli gpt gene and the gene for the green fluorescent protein. The US28 gene is not required for growth in human fibroblasts (HF). HF infected with wild-type HCMV bound RANTES at 24 h postinfection and demonstrated an intracellular calcium flux induced by RANTES. In cells infected with HV5.8, RANTES did not bind or induce a calcium flux, demonstrating that US28 is responsible for the beta-chemokine binding and induced calcium signaling in HCMV-infected cells. The ability of the US28 gene to bind chemokines was shown to cause a significant reduction in the concentration of RANTES in the medium of infected cells. Northern analysis of RNA from infected cells showed that US28 is an early gene, while US27 (another GCR) is a late gene.
Collapse
Affiliation(s)
- J Vieira
- Department of Laboratory Medicine, University of Washington, Seattle, Washington 98195, USA.
| | | | | | | |
Collapse
|
50
|
Cao J, Geballe AP. Ribosomal release without peptidyl tRNA hydrolysis at translation termination in a eukaryotic system. RNA 1998; 4:181-188. [PMID: 9570317 PMCID: PMC1369606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A 22-codon upstream open reading frame (uORF2) in the human cytomegalovirus UL4 transcript leader inhibits downstream translation in cis. Previous studies revealed that the peptide product of uORF2 mediates this inhibitory effect by interfering with translation termination at its own stop codon. The block at termination results both in accumulation of the nascent uORF2 peptide linked to tRNA(Pro), the tRNA that decodes the final codon of uORF2, and in stalling of ribosomes at the end of uORF2. The stalled ribosomes create a barrier that obstructs ribosomal transit to the downstream cistron. In the current studies, we further investigated the mechanism of uORF2-mediated translational inhibition by assessing the kinetics of uORF2 peptidyl tRNA(Pro) hydrolysis and ribosomal release from the uORF2 termination site. Whereas hydrolysis of a mutant, noninhibitory uORF2 peptidyl tRNA is nearly complete in less than 1 min, hydrolysis of the wild-type peptidyl tRNA is negligible even after 30 min. In spite of this remarkably prolonged block to hydrolysis of the uORF2 peptidyl tRNA(Pro), most ribosomes are released from the uORF2 termination site within 15 min. Thus, peptidyl tRNA hydrolysis is not absolutely required for ribosomal release in this system. These results suggest that a eukaryotic cellular mechanism exists for removing stalled ribosomes from mRNAs in the absence of peptidyl tRNA hydrolysis.
Collapse
Affiliation(s)
- J Cao
- Division of Molecular Medicine, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | | |
Collapse
|