Transcriptional regulation of gene expression at the genetic and epigenetic level

The synthesis of rRNA is the rate-limiting step in ribosome biogenesis. Conditions that stimulate cell growth, such as growth factors and nutrients, activate rDNA transcription, whereas external signals that harm cell growth inhibit transcription.

Ribosome biogenesis consumes a tremendous amount of cellular energy, and therefore is tightly linked to cell growth and proliferation. The synthesis of rRNA, the first step in ribosome biogenesis, is intricately regulated to be responsive to general metabolism and specific environmental challenges. Actually, almost all signalling pathways that affect cell growth and proliferation directly regulate rRNA synthesis, their downstream effectors converging at the Pol I transcription machinery.




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