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Disruption of CTCF-YY1-dependent looping of the human papillomavirus genome activates differentiation-induced viral oncogene transcription.

Published version
Peer-reviewed

Type

Article

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Authors

Pentland, Ieisha 
Campos-León, Karen 
Cotic, Marius 
Davies, Kelli-Jo 
Wood, C David 

Abstract

The complex life cycle of oncogenic human papillomavirus (HPV) initiates in undifferentiated basal epithelial keratinocytes where expression of the E6 and E7 oncogenes is restricted. Upon epithelial differentiation, E6/E7 transcription is increased through unknown mechanisms to drive cellular proliferation required to support virus replication. We report that the chromatin-organising CCCTC-binding factor (CTCF) promotes the formation of a chromatin loop in the HPV genome that epigenetically represses viral enhancer activity controlling E6/E7 expression. CTCF-dependent looping is dependent on the expression of the CTCF-associated Yin Yang 1 (YY1) transcription factor and polycomb repressor complex (PRC) recruitment, resulting in trimethylation of histone H3 at lysine 27. We show that viral oncogene up-regulation during cellular differentiation results from YY1 down-regulation, disruption of viral genome looping, and a loss of epigenetic repression of viral enhancer activity. Our data therefore reveal a key role for CTCF-YY1-dependent looping in the HPV life cycle and identify a regulatory mechanism that could be disrupted in HPV carcinogenesis.

Description

Keywords

CCCTC-Binding Factor, Cell Differentiation, Chromatin, DNA-Binding Proteins, Down-Regulation, Epigenesis, Genetic, Histones, Humans, Papillomaviridae, Promoter Regions, Genetic, Repressor Proteins, Transcription Factors, Transcriptional Activation, Virus Replication, YY1 Transcription Factor

Journal Title

PLoS Biol

Conference Name

Journal ISSN

1544-9173
1545-7885

Volume Title

16

Publisher

Public Library of Science (PLoS)