Thinking quantitatively about transcriptional regulation (original) (raw)

Transcription is the primary regulatory process that is used by cells, tissues and organisms to facilitate and control the complex programmes of gene expression, cellular metabolism, and organ and tissue development. Many aberrant events that lead to the development of tumours and cancer also depend on transcription. At the chemical level, transcription means 'copying' into RNA transcripts (mRNA, tRNA or rRNA) the portions of the template strand of the DNA genome that correspond to genes. In effect, monomeric ribonucleotides are bound specifically and sequentially to the DNA template at the 3′ end of the growing RNA chain by Watson-Crick base pairing and are polymerized into covalently linked transcripts by enzymes, known as RNA polymerases, that advance processively along the DNA template and catalyse inter-nucleotide-bond formation. Inter-and intracellular signalling networkswhich control transcription factors that operate directly on the regulatory DNA sequences surrounding the PROMOTERS of specific genes -direct the function of the RNA polymerases and therefore control which genes are activated and transcribed, and which are not, at various stages of the cell cycle.