Supporting this hypothesis, transcripts originating from enhancers upstream of the Cyclin D1 gene are thought to serve as adaptors for the recruitment of histone acetyltransferases.
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It was found that depletion of these eRNAs led to Cyclin D1 transcriptional silencing.
The biology of HPV+ OPC is distinct of HPV- OPC with P53 degradation (inactivated by E6 instead of by genetic mutation), pRB pathway inactivation (by E7 instead of Cyclin D1 amplification), and P16 upregulation (over-expression of p16 instead of inactivation due to reduced negative feedback from pRB).
Cyclin D1 | cyclin A | Cyclin-dependent kinase | Cyclin A1 | cyclin |
SMAR1 (Scaffold/Matrix attachment region-binding protein 1; also known as BANP), a tumour-suppressor MAR-binding protein that down-regulates Cyclin D1 expression by recruiting HDAC1-mSin3A co-repressor complex at Cyclin D1 promoter locus; SMAR1 is the target of prostaglandin A2 (PGA2) induced growth arrest.