Genome-wide siRNA screen identifies SMCX, EP400, and Brd4 as E2-dependent regulators of human papillomavirus oncogene expression.
An essential step in the pathogenesis of human papillomavirus (HPV)-associated cancers is the dysregulated expression of the viral oncogenes. The papillomavirus E2 protein can silence the long control region (LCR) promoter that controls viral E6 and E7 oncogene expression. The mechanisms by which E2 represses oncogene expression and the cellular factors through which E2 mediates this silencing are largely unknown. We conducted an unbiased, genome-wide siRNA screen and series of secondary screens that identified 96 cellular genes that contribute to the repression of the HPV LCR. In addition to confirming a role for the E2-binding bromodomain protein Brd4 in E2-mediated silencing, we identified a number of genes that have not previously been implicated in E2 repression, including the demethylase JARID1C/SMCX as well as EP400, a component of the NuA4/TIP60 histone acetyltransferase complex. Each of these genes contributes independently and additively to E2-mediated silencing, indicating that E2 functions through several distinct cellular complexes to repress E6 and E7 expression.
Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
Jennifer A
JA
Smith
Elizabeth A
EA
White
Mathew E
ME
Sowa
Maria L C
ML
Powell
Matthias
M
Ottinger
J Wade
JW
Harper
Peter M
PM
Howley
D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005260:Female; D015967:Gene Expression Regulation, Viral; D020868:Gene Silencing; D055106:Genome-Wide Association Study; D006367:HeLa Cells; D056466:Histone Demethylases; D052161:Human papillomavirus 18 / Q000235:genetics*; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000235:genetics* / Q000378:metabolism; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics / Q000378:metabolism*; D030361:Papillomavirus Infections / Q000378:metabolism / Q000821:virology; D034741:RNA, Small Interfering / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D002583:Uterine Cervical Neoplasms / Q000378:metabolism / Q000821:virology; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication / Q000235:genetics; D000092468:Bromodomain Containing Proteins
D018797:Cell Cycle Proteins; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D056466:Histone Demethylases; D009687:Nuclear Proteins; D009856:Oncogene Proteins, Viral; D010089:Oxidoreductases, N-Demethylating; D034741:RNA, Small Interfering; D014157:Transcription Factors; D014764:Viral Proteins; C441289:BRD4 protein, human; D000092468:Bromodomain Containing Proteins; C051550:E2 protein, Bovine papillomavirus; C054855:E2 protein, Human papillomavirus type 16; C052603:E6 protein, Human papillomavirus type 18; C052633:E7 protein, Human papillomavirus type 18; C086877:KDM5C protein, human; C498558:EP400 protein, human