BIOL 222 Lecture Notes - Lecture 17: Corepressor, Cyclic Adenosine Monophosphate, Catabolism
Document Summary
Biol 222 lecture 17 gene expression. Regulation of gene expression involves protein-nucleic acid and protein-protein interaction. Several levels of regulation: initiation of transcription (repression, activation, alternative sigma factors, regulated transcription termination (attenuation, anti-termination, mrna stability, efficiency of translation (availability of the sd sequence) Regulatory proteins control transcription - activation (positive control) or repression (negative control) Operon genetic unit of coordinate expression. Promoter (p) nucleotide sequence recognized by the subunit of rnap (-10 and -35 sequences) Operator (o) nucleotide sequence recognized by a repressor protein. Structural genes (zya) encode mrna that is translated into proteins. Goal is to maintain homeostatic levels of gene products by regulating gene expression. A turned off gene still has a small amount of expression. Repressor binds to the promoter to stop enzyme binding. Negative inducible operon (repressive mechanism 1) default is off : repressor binds to operator and inhibits transcription by blocking rnap binding, very little transcription, induction relief of repression.
