1
|
Marshall CB, Mays DJ, Beeler JS, Rosenbluth JM, Boyd KL, Santos Guasch GL, Shaver TM, Tang LJ, Liu Q, Shyr Y, Venters BJ, Magnuson MA, Pietenpol JA. p73 Is Required for Multiciliogenesis and Regulates the Foxj1-Associated Gene Network. Cell Rep 2016; 14:2289-300. [PMID: 26947080 DOI: 10.1016/j.celrep.2016.02.035] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 01/26/2016] [Accepted: 02/02/2016] [Indexed: 12/11/2022] Open
Abstract
We report that p73 is expressed in multiciliated cells (MCCs), is required for MCC differentiation, and directly regulates transcriptional modulators of multiciliogenesis. Loss of ciliary biogenesis provides a unifying mechanism for many phenotypes observed in p73 knockout mice including hydrocephalus; hippocampal dysgenesis; sterility; and chronic inflammation/infection of lung, middle ear, and sinus. Through p73 and p63 ChIP-seq using murine tracheal cells, we identified over 100 putative p73 target genes that regulate MCC differentiation and homeostasis. We validated Foxj1, a transcriptional regulator of multiciliogenesis, and many other cilia-associated genes as direct target genes of p73 and p63. We show p73 and p63 are co-expressed in a subset of basal cells and suggest that p73 marks these cells for MCC differentiation. In summary, p73 is essential for MCC differentiation, functions as a critical regulator of a transcriptome required for MCC differentiation, and, like p63, has an essential role in development of tissues.
Collapse
Affiliation(s)
- Clayton B Marshall
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Deborah J Mays
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - J Scott Beeler
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Jennifer M Rosenbluth
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA; Department of Medicine, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Kelli L Boyd
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA
| | | | - Timothy M Shaver
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Lucy J Tang
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Qi Liu
- Center for Quantitative Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Yu Shyr
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA; Center for Quantitative Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Bryan J Venters
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Mark A Magnuson
- Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Jennifer A Pietenpol
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA.
| |
Collapse
|
2
|
Eby KG, Rosenbluth JM, Mays DJ, Marshall CB, Barton CE, Sinha S, Johnson KN, Tang L, Pietenpol JA. ISG20L1 is a p53 family target gene that modulates genotoxic stress-induced autophagy. Mol Cancer 2010; 9:95. [PMID: 20429933 PMCID: PMC2873442 DOI: 10.1186/1476-4598-9-95] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 04/29/2010] [Indexed: 01/28/2023] Open
Abstract
Background Autophagy is characterized by the sequestration of cytoplasm and organelles into multimembrane vesicles and subsequent degradation by the cell's lysosomal system. It is linked to many physiological functions in human cells including stress response, protein degradation, organelle turnover, caspase-independent cell death and tumor suppression. Malignant transformation is frequently associated with deregulation of autophagy and several tumor suppressors can modulate autophagic processes. The tumor suppressor p53 can induce autophagy after metabolic or genotoxic stress through transcriptionally-dependent and -independent mechanisms. In this study we expand on the former mechanism by functionally characterizing a p53 family target gene, ISG20L1 under conditions of genotoxic stress. Results We identified a p53 target gene, ISG20L1, and show that transcription of the gene can be regulated by all three p53 family members (p53, p63, and p73). We generated an antibody to ISG20L1 and found that it localizes to the nucleolar and perinucleolar regions of the nucleus and its protein levels increase in a p53- and p73-dependent manner after various forms of genotoxic stress. When ectopically expressed in epithelial cancer-derived cell lines, ISG20L1 expression decreased clonogenic survival without a concomitant elevation in apoptosis and this effect was partially rescued in cells that were ATG5 deficient. Knockdown of ISG20L1 did not alter 5-FU induced apoptosis as assessed by PARP and caspase-3 cleavage, sub-G1 content, and DNA laddering. Thus, we investigated the role of ISG20L1 in autophagy, a process commonly associated with type II cell death, and found that ISG20L1 knockdown decreased levels of autophagic vacuoles and LC3-II after genotoxic stress as assessed by electron microscopy, biochemical, and immunohistochemical measurements of LC3-II. Conclusions Our identification of ISG20L1 as a p53 family target and discovery that modulation of this target can regulate autophagic processes further strengthens the connection between p53 signaling and autophagy. Given the keen interest in targeting autophagy as an anticancer therapeutic approach in tumor cells that are defective in apoptosis, investigation of genes and signaling pathways involved in cell death associated with autophagy is critical.
Collapse
Affiliation(s)
- Kathryn G Eby
- Department of Biochemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Abstract
p53 and p63 belong to a family of sequence-specific transcription factors regulating key cellular processes. Differential composition of the p53 and p63 DNA-binding sites may contribute to distinct functions of these protein homologues. We used SELEX (systematic evolution of ligands by exponential enrichment) methodology to identify nucleic acid ligands for p63. We found that p63 bound preferentially to DNA fragments conforming to the 20 bp sequence 5'-RRRC(A/G)(A/T)GYYYRRRC(A/T)(C/T)GYYY-3'. Relative to the p53 consensus, the p63 consensus DNA-binding site (DBS) was more degenerate, particularly at positions 10 and 11, and was enriched for A/G at position 5 and C/T at position 16 of the consensus. The differences in DNA-binding site preferences between p63 and p53 influenced their ability to activate transcription from select response elements (REs) in cells. A computer algorithm, p63MH, was developed to find candidate p63-binding motifs on input sequences. We identified genes responsive to p63 regulation that contain functional p63 REs. Our results suggest that the sequence composition of REs could be one contributing factor to target gene discrimination between p63 and p53.
Collapse
Affiliation(s)
- C A Perez
- Department of Biochemistry, Center in Molecular Toxicology, The Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | | | | |
Collapse
|
4
|
Hearnes JM, Mays DJ, Schavolt KL, Tang L, Jiang X, Pietenpol JA. Chromatin immunoprecipitation-based screen to identify functional genomic binding sites for sequence-specific transactivators. Mol Cell Biol 2005; 25:10148-58. [PMID: 16260627 PMCID: PMC1280257 DOI: 10.1128/mcb.25.22.10148-10158.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [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: 04/13/2005] [Revised: 06/06/2005] [Accepted: 08/28/2005] [Indexed: 02/05/2023] Open
Abstract
In various human diseases, altered gene expression patterns are often the result of deregulated gene-specific transcription factor activity. To further understand disease on a molecular basis, the comprehensive analysis of transcription factor signaling networks is required. We developed an experimental approach, combining chromatin immunoprecipitation (ChIP) with a yeast-based assay, to screen the genome for transcription factor binding sites that link to transcriptionally regulated target genes. We used the tumor suppressor p53 to demonstrate the effectiveness of the method. Using primary and immortalized, nontransformed cultures of human mammary epithelial cells, we isolated over 100 genomic DNA fragments that contain novel p53 binding sites. This approach led to the identification and validation of novel p53 target genes involved in diverse signaling pathways, including growth factor signaling, protein kinase/phosphatase signaling, and RNA binding. Our results yield a more complete understanding of p53-regulated signaling pathways, and this approach could be applied to any number of transcription factors to further elucidate complex transcriptional networks.
Collapse
Affiliation(s)
- Jamie M Hearnes
- Department of Biochemistry, Center for Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Nashville, TN 37232-6838, USA
| | | | | | | | | | | |
Collapse
|
5
|
Van Dross R, Yao S, Asad S, Westlake G, Mays DJ, Barquero L, Duell S, Pietenpol JA, Browning PJ. Constitutively Active K-cyclin/cdk6 Kinase in Kaposi Sarcoma–Associated Herpesvirus–Infected Cells. ACTA ACUST UNITED AC 2005; 97:656-66. [PMID: 15870436 DOI: 10.1093/jnci/dji113] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [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] [Indexed: 12/16/2022]
Abstract
BACKGROUND Kaposi sarcoma-associated human herpesvirus (KSHV) encodes K-cyclin, a homologue of D-type cellular cyclins, which binds cyclin-dependent kinases to phosphorylate various substrates. K-cyclin/cdk phosphorylates a subset of substrates normally targeted by cyclins D, E, and A. We used cells naturally infected with KSHV to further characterize the biochemical features of K-cyclin. METHODS We used immunoprecipitation with K-cyclin antibodies to examine the association of K-cyclin with cdk2, cdk6, p21Cip1, and p27Kip1 proteins in BC3 cells. We separated populations of BC3 cells enriched in cells in G1, S, or G2/M phases by elutriation and measured K-cyclin protein and the kinase activity of K-cyclin/cdk6 complexes. The half-life of K-cyclin and cyclin D2 proteins was determined by blocking protein synthesis with cycloheximide and measuring proteins in cell lysates by western blot analysis. We fused the entire K-cyclin sequence to the carboxyl-terminal sequence of cellular cyclin D that contains the PEST degradation sequence to produce K-cyclin/D2 and transfected K-cyclin/D2 into K-cyclin-negative cells to investigate the effect of the PEST sequence on K-cyclin's stability. RESULTS Viral K-cyclin interacted with cyclin-dependent kinases cdk2, cdk4, and cdk6 and with the cyclin/cdk inhibitory proteins p21Cip1 and p27Kip1 in BC3 cell lysates. Unlike D-type cyclins, whose expression is cell cycle dependent, the level of K-cyclin was stable throughout the cell cycle, and the kinase associated with the K-cyclin/cdk6 complex was constitutively active. The half-life of K-cyclin (6.9 hours) was much longer than that of cellular cyclin D2 (0.6 hour) and that of K-cyclin/D2 (0.5 hour), probably because K-cyclin lacks the PEST degradation sequence present in D-type cyclins. CONCLUSION The constitutive activation of K-cyclin/cdk complexes in KSHV-infected cells appears to result from the extended half-life of K-cyclin and may explain its role in Kaposi sarcoma.
Collapse
Affiliation(s)
- Rukiyah Van Dross
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City 66160, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Jo D, Lin Q, Nashabi A, Mays DJ, Unutmaz D, Pietenpol JA, Ruley HE. Cell cycle-dependent transduction of cell-permeant Cre recombinase proteins. J Cell Biochem 2003; 89:674-87. [PMID: 12858334 DOI: 10.1002/jcb.10542] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [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: 11/09/2022]
Abstract
Protein transduction has been widely used to analyze biochemical processes in living cells quantitatively and under non-steady-state conditions. The present study analyzed the effects of cell cycle on the uptake and activity of cell-permeant Cre recombinase proteins. Previous studies had suggested that the efficiency of recombination and/or protein transduction varied among individual cells, even within a clonal population. We report here that cells in the G1 phase of the cell cycle undergo recombination at a lower rate than cells at other phases of the cell cycle, and that this variation results largely from differences in protein uptake, associated with differences in cell size. These results have implications regarding the mechanism of protein transduction and identify a source of heterogeneity that can influence the response of individual cells to cell-permeant proteins.
Collapse
Affiliation(s)
- Daewoong Jo
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | | | | | | | | | | | | |
Collapse
|
7
|
Westfall MD, Mays DJ, Sniezek JC, Pietenpol JA. The Delta Np63 alpha phosphoprotein binds the p21 and 14-3-3 sigma promoters in vivo and has transcriptional repressor activity that is reduced by Hay-Wells syndrome-derived mutations. Mol Cell Biol 2003; 23:2264-76. [PMID: 12640112 PMCID: PMC150720 DOI: 10.1128/mcb.23.7.2264-2276.2003] [Citation(s) in RCA: 263] [Impact Index Per Article: 12.5] [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: 07/17/2002] [Revised: 08/21/2002] [Accepted: 01/02/2003] [Indexed: 11/20/2022] Open
Abstract
p63 is a recently identified homolog of p53 that is found in the basal layer of several stratified epithelial tissues such as the epidermis, oral mucosa, prostate, and urogenital tract. Studies with p63(-/-) mice and analysis of several human autosomal-dominant disorders with germ line p63 mutations suggest p63 involvement in maintaining epidermal stem cell populations. The p63 gene encodes six splice variants with reported transactivating or dominant-negative activities. The goals of the current study were to determine the splice variants that are expressed in primary human epidermal keratinocytes (HEKs) and the biochemical activity p63 has in these epithelial cell populations. We found that the predominant splice variant expressed in HEKs was Delta Np63 alpha, and it was present as a phosphorylated protein. During HEK differentiation, Delta Np63 alpha and p53 levels decreased, while expression of p53 target genes p21 and 14-3-3 sigma increased. Delta Np63 alpha had transcriptional repressor activity in vitro, and this activity was reduced in Delta Np63 alpha proteins containing point mutations, corresponding to those found in patients with Hay-Wells syndrome. Further, we show that Delta Np63 alpha and p53 can bind the p21 and 14-3-3 sigma promoters in vitro and in vivo, with decreased binding of p63 to these promoters during HEK differentiation. These data suggest that Delta Np63 alpha acts as a transcriptional repressor at select growth regulatory gene promoters in HEKs, and this repression likely plays an important role in the proliferative capacity of basal keratinocytes.
Collapse
Affiliation(s)
- Matthew D Westfall
- Department of Biochemistry, Center in Molecular Toxicology, The Vanderbilt-Ingram Comprehensive Cancer Center, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | | | | | | |
Collapse
|
8
|
Peek RM, Blaser MJ, Mays DJ, Forsyth MH, Cover TL, Song SY, Krishna U, Pietenpol JA. Helicobacter pylori strain-specific genotypes and modulation of the gastric epithelial cell cycle. Cancer Res 1999; 59:6124-31. [PMID: 10626802] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Helicobacter pylori cag+ strains enhance gastric epithelial cell proliferation and attenuate apoptosis in vivo, which may partially explain the increased risk of gastric cancer associated with these strains. The goals of this study were to identify specific H. pylori genes that regulate epithelial cell cycle events and determine whether these effects were dependent upon p53-mediated pathways. AGS gastric epithelial cells were cultured alone or in the presence of 21 clinical H. pylori isolates, H. pylori reference strain 60190, or its isogenic cagA-, picB-, vacA-, or picB-/vacA- derivatives. Coculture of H. pylori with AGS cells significantly decreased cell viability, an effect most prominent with cag+ strains (P < 0.001 versus cag-strains). cag+ strains significantly increased progression of AGS cells from G1 into G2-M at 6 h and enhanced apoptosis by 72 h. Compared with the parental 60190 strain, the picB- mutant attenuated cell cycle progression at 6 h (P < or = 0.05), and decreased apoptosis with enhanced AGS cell viability at 24 h (P < or = 0.04). The vacA- mutant decreased apoptosis and enhanced viability at later (48-72 h) time points (P < or = 0.05). Compared with the wild-type strain, the picB-/vacA- double mutant markedly attenuated apoptosis and increased cell viability at all time points (P < or = 0.05). Furthermore, cocolonization with H. pylori had no significant effect on expression of p53, p21, and MDM2. The diminished AGS cell viability, progression to G2-M, and apoptosis associated with cag+ H. pylori strains were dependent upon expression of vacA and genes within the cag pathogenicity island. These results may explain heterogeneity in levels of gastric epithelial cell proliferation and apoptosis found within H. pyloricolonized mucosa.
Collapse
Affiliation(s)
- R M Peek
- Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2279, USA.
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Abstract
The cloned Kv1.5 K+ channel displays similar kinetics and pharmacology to a delayed rectifier channel found in atrial myocytes. To determine whether the Kv1.5 isoform plays a role in the cardiac action potential, it is necessary to confirm the expression of this channel in cardiac myocytes. Using antibodies directed against two distinct channel epitopes, the Kv1.5 isoform was localized in human atrium and ventricle. Kv1.5 was highly localized at intercalated disk regions as determined by colocalization with connexin and N-cadherin specific antibodies. While both antichannel antibodies localized the Kv1.5 protein in cardiac myocytes, only the NH2-terminal antibodies stained vascular smooth muscle. The selective staining of vasculature by this antiserum suggests that epitope accessibility, and perhaps channel structure, varies between cardiac and vascular myocytes. Kv1.5 expression was localized less in newborn tissue, with punctate antibody staining dispersed on the myocyte surface. This increasing organization with age was similar to that observed for connexin. Future work will address whether altered K+ channel localization is associated with cardiac disease in addition to changing with development.
Collapse
Affiliation(s)
- D J Mays
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | | | | | | |
Collapse
|