Document Detail

Human papillomavirus type 16 E1 E4-induced G2 arrest is associated with cytoplasmic retention of active Cdk1/cyclin B1 complexes.
MedLine Citation:
PMID:  15767402     Owner:  NLM     Status:  MEDLINE    
Human papillomavirus type 16 (HPV16) can cause cervical cancer. Expression of the viral E1 E4 protein is lost during malignant progression, but in premalignant lesions, E1 E4 is abundant in cells supporting viral DNA amplification. Expression of 16E1 E4 in cell culture causes G2 cell cycle arrest. Here we show that unlike many other G2 arrest mechanisms, 16E1 E4 does not inhibit the kinase activity of the Cdk1/cyclin B1 complex. Instead, 16E1 E4 uses a novel mechanism in which it sequesters Cdk1/cyclin B1 onto the cytokeratin network. This prevents the accumulation of active Cdk1/cyclin B1 complexes in the nucleus and hence prevents mitosis. A mutant 16E1 E4 (T22A, T23A) which does not bind cyclin B1 or alter its intracellular location fails to induce G2 arrest. The significance of these results is highlighted by the observation that in lesions induced by HPV16, there is evidence for Cdk1/cyclin B1 activity on the keratins of 16E1 E4-expressing cells. We hypothesize that E1 E4-induced G2 arrest may play a role in creating an environment optimal for viral DNA replication and that loss of E1 E4 expression may contribute to malignant progression.
Clare E Davy; Deborah J Jackson; Kenneth Raj; Woei Ling Peh; Shirley A Southern; Papia Das; Rina Sorathia; Peter Laskey; Kate Middleton; Tomomi Nakahara; Qian Wang; Phillip J Masterson; Paul F Lambert; Scott Cuthill; Jonathan B A Millar; John Doorbar
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of virology     Volume:  79     ISSN:  0022-538X     ISO Abbreviation:  J. Virol.     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-03-15     Completed Date:  2005-04-26     Revised Date:  2014-02-19    
Medline Journal Info:
Nlm Unique ID:  0113724     Medline TA:  J Virol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3998-4011     Citation Subset:  IM    
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MeSH Terms
CDC2 Protein Kinase / metabolism*
COS Cells
Cell Line, Tumor
Cell Nucleus / chemistry
Cyclin B / metabolism*
Cyclin B1
Cytoplasm / chemistry
DNA Replication
G2 Phase / physiology*
Keratins / metabolism
Oncogene Proteins, Fusion / genetics,  physiology*
Papillomaviridae / pathogenicity,  physiology*
Point Mutation
Viral Proteins / genetics,  physiology*
Virus Replication
Grant Support
MC_U117531948//Medical Research Council; MC_U117584278//Medical Research Council
Reg. No./Substance:
0/CCNB1 protein, human; 0/Cyclin B; 0/Cyclin B1; 0/Oncogene Proteins, Fusion; 0/Viral Proteins; 0/oncogene protein E1--E4, Human papillomavirus type 16; 68238-35-7/Keratins; EC Protein Kinase

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