Interactions of the cellular CCAAT displacement protein and human papillomavirus E2 protein with the viral origin of replication can regulate DNA replication.
Previously, we and others have shown that CCAAT displacement protein (CDP) negatively regulates the papillomavirus promoters. Overexpression of CDP has been shown to inhibit high-risk human papillomavirus virus (HPV) and bovine papillomavirus DNA replication in vivo presumably through reduction in expression of viral replication proteins, E1 and E2. Sequence analysis of the HPV origin indicates several potential CDP-binding sites with one site overlapping the E1-binding site. Therefore, CDP could also negatively regulate papillomavirus replication directly by preventing the loading of the initiation complex. We show here that purified CDP inhibits in vitro HPV DNA replication. Footprint analysis demonstrated that CDP binds the E1-binding site and the TATA box, and that the binding of purified CDP to the E1-binding site is decreased by the addition of purified E2 protein. Consistent with this, E2-independent in vitro HPV replication is inhibited by CDP to a greater extent than E2-dependent replication. These results suggest that binding of E2 at the E2-binding site may play an important role in overcoming the inhibition of E1 initiation complex formation caused by the binding of negative regulators like CDP to the origin of replication.
Narahari
Janaki
J
Department of Microbiology and Immunology, Indiana University School of Medicine and Walther Cancer Institute, Indianapolis, IN 46202, USA. jnarahar@iupui.edu
Fisk
John C
JC
Melendy
Thomas
T
Roman
Ann
A
D001483:Base Sequence; D001665:Binding Sites; D018983:DNA Footprinting; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003850:Deoxyribonuclease I; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D027383:Papillomaviridae / Q000235:genetics*; D018741:Replication Origin; D012097:Repressor Proteins / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors; D014764:Viral Proteins / Q000378:metabolism*
C080632:CUX1 protein, human; D004268:DNA-Binding Proteins; C118863:E1 protein, Human papillomavirus type 31; C098597:E2 protein, Human papillomavirus type 31; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D003850:Deoxyribonuclease I