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Rheinemann L, Downhour DM, Davenport KA, McKeown AN, Sundquist WI, Elde NC. Recurrent evolution of an inhibitor of ESCRT-dependent virus budding and LINE-1 retrotransposition in primates. Curr Biol 2022; 32:1511-1522.e6. [PMID: 35245459 PMCID: PMC9007875 DOI: 10.1016/j.cub.2022.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 12/20/2021] [Accepted: 02/03/2022] [Indexed: 12/15/2022]
Abstract
Most antiviral proteins recognize specific features of viruses. In contrast, the recently described antiviral factor retroCHMP3 interferes with the "host endosomal complexes required for transport" (ESCRT) pathway to inhibit the budding of enveloped viruses. RetroCHMP3 arose independently on multiple occasions via duplication and truncation of the gene encoding the ESCRT-III factor CHMP3. However, since the ESCRT pathway is essential for cellular membrane fission reactions, ESCRT inhibition is potentially cytotoxic. This raises fundamental questions about how hosts can repurpose core cellular functions into antiviral functions without incurring a fitness cost due to excess cellular toxicity. We reveal the evolutionary process of detoxification for retroCHMP3 in New World monkeys using a combination of ancestral reconstructions, cytotoxicity, and virus release assays. A duplicated, full-length copy of retroCHMP3 in the ancestors of New World monkeys provides modest inhibition of virus budding while exhibiting subtle cytotoxicity. Ancient retroCHMP3 then accumulated mutations that reduced cytotoxicity but preserved virus inhibition before a truncating stop codon arose in the more recent ancestors of squirrel monkeys, resulting in potent inhibition. In species where full-length copies of retroCHMP3 still exist, their artificial truncation generated potent virus-budding inhibitors with little cytotoxicity, revealing the potential for future antiviral defenses in modern species. In addition, we discovered that retroCHMP3 restricts LINE-1 retrotransposition, revealing how different challenges to genome integrity might explain multiple independent origins of retroCHMP3 in different species to converge on new immune functions.
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Affiliation(s)
- Lara Rheinemann
- Department of Biochemistry, University of Utah School of Medicine, 15 N Medical Drive East, Salt Lake City, UT 84112, USA
| | - Diane Miller Downhour
- Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E, Salt Lake City, UT 84112, USA
| | - Kristen A Davenport
- Department of Biochemistry, University of Utah School of Medicine, 15 N Medical Drive East, Salt Lake City, UT 84112, USA; Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E, Salt Lake City, UT 84112, USA
| | - Alesia N McKeown
- Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E, Salt Lake City, UT 84112, USA
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of Medicine, 15 N Medical Drive East, Salt Lake City, UT 84112, USA
| | - Nels C Elde
- Department of Human Genetics, University of Utah School of Medicine, 15 N 2030 E, Salt Lake City, UT 84112, USA; Howard Hughes Medical Institute, 4000 Jones Bridge Rd, Chevy Chase, MD 20815, USA.
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Garstang MG, Ferrier DEK. Amphioxus SYCP1: a case of retrogene replacement and co-option of regulatory elements adjacent to the ParaHox cluster. Dev Genes Evol 2018; 228:13-30. [PMID: 29297095 PMCID: PMC5803294 DOI: 10.1007/s00427-017-0600-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/08/2017] [Indexed: 01/26/2023]
Abstract
Retrogenes are formed when an mRNA is reverse-transcribed and reinserted into the genome in a location unrelated to the original locus. If this retrocopy inserts into a transcriptionally favourable locus and is able to carry out its original function, it can, in rare cases, lead to retrogene replacement. This involves the original, often multi-exonic, parental copy being lost whilst the newer single-exon retrogene copy 'replaces' the role of the ancestral parent gene. One example of this is amphioxus SYCP1, a gene that encodes a protein used in synaptonemal complex formation during meiosis and which offers the opportunity to examine how a retrogene evolves after the retrogene replacement event. SYCP1 genes exist as large multi-exonic genes in most animals. AmphiSYCP1, however, contains a single coding exon of ~ 3200 bp and has inserted next to the ParaHox cluster of amphioxus, whilst the multi-exonic ancestral parental copy has been lost. Here, we show that AmphiSYCP1 has not only replaced its parental copy, but also has evolved additional regulatory function by co-opting a bidirectional promoter from the nearby AmphiCHIC gene. AmphiSYCP1 has also evolved a de novo, multi-exonic 5'untranslated region that displays distinct regulatory states, in the form of two different isoforms, and has evolved novel expression patterns during amphioxus embryogenesis in addition to its ancestral role in meiosis. The absence of ParaHox-like expression of AmphiSYCP1, despite its proximity to the ParaHox cluster, also suggests that this gene is not influenced by any potential pan-cluster regulatory mechanisms, which are seemingly restricted to only the ParaHox genes themselves.
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Affiliation(s)
- Myles G Garstang
- The Scottish Oceans Institute, Gatty Marine Laboratory, University of St Andrews, East Sands, St Andrews, Fife, KY16 8LB, UK.,School of Biological Sciences, University of Essex, Wivenhoe, Colchester, Essex, CO4 3SQ, UK
| | - David E K Ferrier
- The Scottish Oceans Institute, Gatty Marine Laboratory, University of St Andrews, East Sands, St Andrews, Fife, KY16 8LB, UK.
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Protein-Coding Genes' Retrocopies and Their Functions. Viruses 2017; 9:v9040080. [PMID: 28406439 PMCID: PMC5408686 DOI: 10.3390/v9040080] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/07/2017] [Accepted: 04/11/2017] [Indexed: 12/11/2022] Open
Abstract
Transposable elements, often considered to be not important for survival, significantly contribute to the evolution of transcriptomes, promoters, and proteomes. Reverse transcriptase, encoded by some transposable elements, can be used in trans to produce a DNA copy of any RNA molecule in the cell. The retrotransposition of protein-coding genes requires the presence of reverse transcriptase, which could be delivered by either non-long terminal repeat (non-LTR) or LTR transposons. The majority of these copies are in a state of “relaxed” selection and remain “dormant” because they are lacking regulatory regions; however, many become functional. In the course of evolution, they may undergo subfunctionalization, neofunctionalization, or replace their progenitors. Functional retrocopies (retrogenes) can encode proteins, novel or similar to those encoded by their progenitors, can be used as alternative exons or create chimeric transcripts, and can also be involved in transcriptional interference and participate in the epigenetic regulation of parental gene expression. They can also act in trans as natural antisense transcripts, microRNA (miRNA) sponges, or a source of various small RNAs. Moreover, many retrocopies of protein-coding genes are linked to human diseases, especially various types of cancer.
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Carelli FN, Hayakawa T, Go Y, Imai H, Warnefors M, Kaessmann H. The life history of retrocopies illuminates the evolution of new mammalian genes. Genome Res 2016; 26:301-14. [PMID: 26728716 PMCID: PMC4772013 DOI: 10.1101/gr.198473.115] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/21/2015] [Indexed: 02/03/2023]
Abstract
New genes contribute substantially to adaptive evolutionary innovation, but the functional evolution of new mammalian genes has been little explored at a broad scale. Previous work established mRNA-derived gene duplicates, known as retrocopies, as models for the study of new gene origination. Here we combine mammalian transcriptomic and epigenomic data to unveil the processes underlying the evolution of stripped-down retrocopies into complex new genes. We show that although some robustly expressed retrocopies are transcribed from preexisting promoters, most evolved new promoters from scratch or recruited proto-promoters in their genomic vicinity. In particular, many retrocopy promoters emerged from ancestral enhancers (or bivalent regulatory elements) or are located in CpG islands not associated with other genes. We detected 88–280 selectively preserved retrocopies per mammalian species, illustrating that these mechanisms facilitated the birth of many functional retrogenes during mammalian evolution. The regulatory evolution of originally monoexonic retrocopies was frequently accompanied by exon gain, which facilitated co-option of distant promoters and allowed expression of alternative isoforms. While young retrogenes are often initially expressed in the testis, increased regulatory and structural complexities allowed retrogenes to functionally diversify and evolve somatic organ functions, sometimes as complex as those of their parents. Thus, some retrogenes evolved the capacity to temporarily substitute for their parents during the process of male meiotic X inactivation, while others rendered parental functions superfluous, allowing for parental gene loss. Overall, our reconstruction of the “life history” of mammalian retrogenes highlights retroposition as a general model for understanding new gene birth and functional evolution.
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Affiliation(s)
- Francesco Nicola Carelli
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Takashi Hayakawa
- Department of Wildlife Science (Nagoya Railroad Company, Limited), Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan; Japan Monkey Center, Inuyama, Aichi 484-0081, Japan
| | - Yasuhiro Go
- Department of Brain Sciences, Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, Aichi 444-8585, Japan; Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 484-8585, Japan
| | - Hiroo Imai
- Department of Cellular and Molecular Biology, Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Maria Warnefors
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Henrik Kaessmann
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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