Adenovirus E1A activates cyclin A gene transcription in the absence of growth factors through interaction with p107.
AUTOR(ES)
Zerfass, K
RESUMO
Using the infection of quiescent human fibroblasts with adenovirus type 5 and various deletion mutants, we show that E1A can stimulate transcription of the cyclin A gene in the absence of exogenous growth factors. Required for this activity is conserved region 2 (CR2), while both the N-terminal part of E1A and CR1 are dispensable. This indicates that activation of cyclin A gene expression requires the binding of E1A to p107, while binding to either pRB or p300 is not involved in transcriptional activation. We demonstrate that p107 represses the cyclin A promoter through its cell cycle-regulatory E2F binding site and that 12S E1A can activate the cyclin A promoter, essentially by counteracting its repression by p107. Since Cr2 is required for cell transformation, transcriptional activation of the cyclin A gene by E1A appears to be important for its capacity to override control of cellular growth.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=190115Documentos Relacionados
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