Cell cycle transcriptional repression/genes

The cell cycle encompasses so many different processes that it is clearly impossible to describe it by the single diagram of Fig. 11-15 or by the text written here. The cycle is influenced by a host of growth factors and external stimuli, many of which act on transcription of cyclins and other essential proteins. Transcription factors such as those of the Fos / Jim (AP-1) family in response to the MAP cascade (Fig. 11-13) are among those that control the transcription of cyclins.262 263c However, during mitosis most transcription of any genes is repressed 264... 

J. Zwicker, F. C. Lucibello, L. A. Wolfraim, C. Gross, M. Truss, K. Engeland, and R. Muller, Cell cycle regulation of the cyclin A, cdc25C and cdc2 genes is based on a common mechanism of transcriptional repression, EMBO J. 74 4514 (1995). 

The RB gene encodes a transcriptional co-repressor which forms a complex with the cell-cycle-regulating transcription factor E2F (members of the E2F family of transcriptional activators control the genes involved in the Gj/S transition and in DNA replication 20 see Chapter 12). The RB—E2F transcriptional complex contains additional factors, such as the histone deacetylase, HDACl, which facilitates access of the transcriptional complex to E2F-responsive gene promoters, such as the cycKn E promoter. pRB and HDACl act in concert and repress the cyclin E promoter. i Hence the retinoblastoma protein (pRB) is a tumour-suppressor that represses gene expression in concert with a histone deacetylase, by modulating the architecture of chromatin (Fig. 15.4). The pRB- E2F transcriptional complex also represses transcription of RNA polymerase III22 (see also Chapter 9). 

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