{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:16:59Z","timestamp":1760242619732,"version":"build-2065373602"},"reference-count":36,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2017,12,19]],"date-time":"2017-12-19T00:00:00Z","timestamp":1513641600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada","doi-asserted-by":"publisher","award":["RGPIN\/435375-2013"],"award-info":[{"award-number":["RGPIN\/435375-2013"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100008794","name":"Research Manitoba","doi-asserted-by":"publisher","award":["Operating Grant"],"award-info":[{"award-number":["Operating Grant"]}],"id":[{"id":"10.13039\/100008794","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Adenovirus Early 1A proteins (E1A) are crucial for initiation of the viral life cycle after infection. The E1A gene is encoded at the left end of the viral genome and consists of two exons, the first encoding 185 amino acids in the 289 residues adenovirus 5 E1A, while the second exon encodes 104 residues. The second exon-encoded region of E1A is conserved across all E1A isoforms except for the 55 residues protein, which has a unique C-terminus due to a frame shift following splicing into the second exon. This region of E1A contributes to a variety of processes including the regulation of viral and cellular gene expression, immortalization and transformation. Here we evaluated the contributions that different regions of the second exon of E1A make to the viral life cycle using deletion mutants. The region of E1A encoded by the second exon was found to be important for overall virus growth, induction of viral and cellular gene expression, viral genome replication and deregulation of the cell cycle. Efficient viral replication was found to require exon 2 and the nuclear localization signal, as loss of either resulted in severe growth deficiency. Induction of cellular DNA synthesis was also deficient with any deletion of E1A within the C-terminus even if these deletions were outside of conserved region 4. Overall, our study provides the first comprehensive insight into the contributions of the C-terminus of E1A to the replicative fitness of human adenovirus 5 in arrested lung fibroblasts.<\/jats:p>","DOI":"10.3390\/v9120387","type":"journal-article","created":{"date-parts":[[2017,12,19]],"date-time":"2017-12-19T10:48:40Z","timestamp":1513680520000},"page":"387","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["The Influence of E1A C-Terminus on Adenovirus Replicative Cycle"],"prefix":"10.3390","volume":"9","author":[{"given":"Leandro","family":"Crisostomo","sequence":"first","affiliation":[{"name":"Department of Microbiology, University of Manitoba, 45 Chancellor\u2019s Circle, Buller Building Room 427, Winnipeg MB R3T 2N2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrea","family":"Soriano","sequence":"additional","affiliation":[{"name":"Department of Microbiology, University of Manitoba, 45 Chancellor\u2019s Circle, Buller Building Room 427, Winnipeg MB R3T 2N2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jasmine","family":"Frost","sequence":"additional","affiliation":[{"name":"Department of Microbiology, University of Manitoba, 45 Chancellor\u2019s Circle, Buller Building Room 427, Winnipeg MB R3T 2N2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Oladunni","family":"Olanubi","sequence":"additional","affiliation":[{"name":"Department of Microbiology, University of Manitoba, 45 Chancellor\u2019s Circle, Buller Building Room 427, Winnipeg MB R3T 2N2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Megan","family":"Mendez","sequence":"additional","affiliation":[{"name":"Department of Microbiology, University of Manitoba, 45 Chancellor\u2019s Circle, Buller Building Room 427, Winnipeg MB R3T 2N2, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Pelka","sequence":"additional","affiliation":[{"name":"Department of Microbiology, University of Manitoba, 45 Chancellor\u2019s Circle, Buller Building Room 427, Winnipeg MB R3T 2N2, Canada"},{"name":"Department of Medical Microbiology, University of Manitoba, Winnipeg MB R3E 0J9, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2017,12,19]]},"reference":[{"key":"ref_1","unstructured":"Knipe, D.M., and Howley, P.M. (2013). Chapter 55. Adenoviridae. Fields Virology, Lippincott Williams & Wilkins. [6th ed.]."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Radko, S., Jung, R., Olanubi, O., and Pelka, P. (2015). Effects of adenovirus type 5 E1A isoforms on viral replication in arrested human cells. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0140124"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"7252","DOI":"10.1128\/JVI.00104-08","article-title":"Intrinsic structural disorder in adenovirus E1A: A viral molecular hub linking multiple diverse processes","volume":"82","author":"Pelka","year":"2008","journal-title":"J. Virol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"10348","DOI":"10.1128\/JVI.00786-13","article-title":"Dissection of the C-terminal region of E1A re-defines the roles of CtBP and other cellular targets in oncogenic transformation","volume":"87","author":"Cohen","year":"2013","journal-title":"J. Virol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"469","DOI":"10.1002\/j.1460-2075.1993.tb05679.x","article-title":"A region in the C-terminus of adenovirus 2\/5 E1A protein is required for association with a cellular phosphoprotein and important for the negative modulation of T24-ras mediated transformation, tumorigenesis and metastasis","volume":"12","author":"Boyd","year":"1993","journal-title":"EMBO J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2719","DOI":"10.1128\/JVI.02119-09","article-title":"Adenovirus type 5 E1A and E6 proteins of low-risk cutaneous beta-human papillomaviruses suppress cell transformation through interaction with FOXK1\/K2 transcription factors","volume":"84","author":"Komorek","year":"2010","journal-title":"J. Virol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1006\/viro.2001.1151","article-title":"Adenoviral E1A protein nuclear import is preferentially mediated by importin alpha3 in vitro","volume":"289","author":"Kohler","year":"2001","journal-title":"Virology"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"699","DOI":"10.1091\/mbc.12.3.699","article-title":"Interaction of the E1A oncoprotein with Yak1p, a novel regulator of yeast pseudohyphal differentiation, and related mammalian kinases","volume":"12","author":"Zhang","year":"2001","journal-title":"Mol. Biol. Cell"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"13469","DOI":"10.1128\/JVI.02538-14","article-title":"Adenovirus E1A targets the DREF nuclear factor to regulate virus gene expression, DNA replication, and growth","volume":"88","author":"Radko","year":"2014","journal-title":"J. Virol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.virol.2016.10.004","article-title":"The interaction of adenovirus E1A with the mammalian protein ku70\/XRCC6","volume":"500","author":"Frost","year":"2016","journal-title":"Virology"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Olanubi, O., Frost, J.R., Radko, S., and Pelka, P. (2017). Suppression of type I interferon signaling by E1A via RuvBL1\/Pontin. J. Virol., 91.","DOI":"10.1128\/JVI.02484-16"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"238","DOI":"10.1016\/j.virol.2014.08.014","article-title":"Functional analysis of the C-terminal region of human adenovirus E1A reveals a misidentified nuclear localization signal","volume":"468","author":"Cohen","year":"2014","journal-title":"Virology"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"533","DOI":"10.1128\/jvi.55.3.533-546.1985","article-title":"Monoclonal antibodies specific for adenovirus early region 1A proteins: Extensive heterogeneity in early region 1A products","volume":"55","author":"Harlow","year":"1985","journal-title":"J. Virol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2027","DOI":"10.1002\/j.1460-2075.1987.tb02467.x","article-title":"Differential splicing yields novel adenovirus 5 E1A mrnas that encode 30 kd and 35 kd proteins","volume":"6","author":"Stephens","year":"1987","journal-title":"EMBO J."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"480","DOI":"10.1016\/0042-6822(83)90274-X","article-title":"Monoclonal antibodies which recognize native and denatured forms of the adenovirus DNA-binding protein","volume":"128","author":"Reich","year":"1983","journal-title":"Virology"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1016\/0092-8674(79)90275-7","article-title":"Isolation of adenovirus type 5 host range deletion mutants defective for transformation of rat embryo cells","volume":"17","author":"Jones","year":"1979","journal-title":"Cell"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"3665","DOI":"10.1073\/pnas.76.8.3665","article-title":"An adenovirus type 5 early gene function regulates expression of other early viral genes","volume":"76","author":"Jones","year":"1979","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"494","DOI":"10.1016\/0042-6822(88)90290-5","article-title":"Use of deletion and point mutants spanning the coding region of the adenovirus 5 E1A gene to define a domain that is essential for transcriptional activation","volume":"163","author":"Jelsma","year":"1988","journal-title":"Virology"},{"key":"ref_19","first-page":"475","article-title":"Efficient nuclear localization of the Ad5 E1A 12S protein is necessary for immortalization but not cotransformation of primary epithelial cells","volume":"5","author":"Douglas","year":"1994","journal-title":"Cell Growth Differ."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"e45","DOI":"10.1093\/nar\/29.9.e45","article-title":"A new mathematical model for relative quantification in real-time RT-PCR","volume":"29","author":"Pfaffl","year":"2001","journal-title":"Nucleic Acids Res."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Reza Etemadi, M., Ling, K.H., Zainal Abidin, S., Chee, H.Y., and Sekawi, Z. (2017). Gene expression patterns induced at different stages of rhinovirus infection in human alveolar epithelial cells. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0176947"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"742","DOI":"10.1128\/jvi.53.3.742-750.1985","article-title":"An adenovirus early region 1A protein is required for maximal viral DNA replication in growth-arrested human cells","volume":"53","author":"Spindler","year":"1985","journal-title":"J. Virol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1128\/jvi.45.1.192-199.1983","article-title":"Adenovirus-induced alterations of the cell growth cycle: A requirement for expression of E1A but not of E1B","volume":"45","author":"Braithwaite","year":"1983","journal-title":"J. Virol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"8841","DOI":"10.1128\/JVI.00539-11","article-title":"Adenovirus E1A directly targets the E2F\/DP-1 complex","volume":"85","author":"Pelka","year":"2011","journal-title":"J. Virol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1139\/o11-080","article-title":"The C-terminal region of E1A: A molecular tool for cellular cartography","volume":"90","author":"Yousef","year":"2012","journal-title":"Biochem. Cell Biol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"8476","DOI":"10.1128\/JVI.00248-08","article-title":"Identification of a second CtBP binding site in adenovirus type 5 E1A conserved region 3","volume":"82","author":"Bruton","year":"2008","journal-title":"J. Virol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1006\/viro.1998.9337","article-title":"The C terminus of E1A regulates tumor progression and epithelial cell differentiation","volume":"249","author":"Fischer","year":"1998","journal-title":"Virology"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1006\/viro.2000.0232","article-title":"While E1A can facilitate epithelial cell transformation by several dominant oncogenes, the C-terminus seems only to regulate RAC and CDC42 function, but in both epithelial and fibroblastic cells","volume":"269","author":"Fischer","year":"2000","journal-title":"Virology"},{"key":"ref_29","first-page":"2093","article-title":"Modulation of transformation of primary epithelial cells by the second exon of the Ad5 E1A12S gene","volume":"6","author":"Douglas","year":"1991","journal-title":"Oncogene"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2020","DOI":"10.1128\/jvi.66.4.2020-2030.1992","article-title":"Immortalization of primary epithelial cells requires first- and second-exon functions of adenovirus type 5 12S","volume":"66","author":"Quinlan","year":"1992","journal-title":"J. Virol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"6922","DOI":"10.1128\/jvi.67.12.6922-6928.1993","article-title":"Induction of gene expression by exon 2 of the major E1A proteins of adenovirus type 5","volume":"67","author":"Mymryk","year":"1993","journal-title":"J. Virol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1931","DOI":"10.1128\/JVI.02392-15","article-title":"The dual nature of Nek9 in adenovirus replication","volume":"90","author":"Jung","year":"2015","journal-title":"J. Virol."},{"key":"ref_33","first-page":"7029","article-title":"Identification of distinct roles for separate E1A domains in disruption of E2F complexes","volume":"13","author":"Ikeda","year":"1993","journal-title":"Mol. Cell. Biol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1016\/j.virol.2014.02.020","article-title":"Identification and characterization of multiple conserved nuclear localization signals within adenovirus E1A","volume":"454","author":"Marshall","year":"2014","journal-title":"Virology"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"5819","DOI":"10.1128\/JVI.74.13.5819-5824.2000","article-title":"The E4-6\/7 protein functionally compensates for the loss of E1A expression in adenovirus infection","volume":"74","author":"Hearing","year":"2000","journal-title":"J. Virol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"8061","DOI":"10.1128\/jvi.69.12.8061-8065.1995","article-title":"Efficient nuclear localization and immortalizing ability, two functions dependent on the adenovirus type 5 (Ad5) E1A second exon, are necessary for cotransformation with Ad5 E1B but not with T24ras","volume":"69","author":"Douglas","year":"1995","journal-title":"J. Virol."}],"container-title":["Viruses"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1999-4915\/9\/12\/387\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:54:31Z","timestamp":1760208871000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1999-4915\/9\/12\/387"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,12,19]]},"references-count":36,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2017,12]]}},"alternative-id":["v9120387"],"URL":"https:\/\/doi.org\/10.3390\/v9120387","relation":{},"ISSN":["1999-4915"],"issn-type":[{"type":"electronic","value":"1999-4915"}],"subject":[],"published":{"date-parts":[[2017,12,19]]}}}