BIOL 330 Lecture Notes - Lecture 11: Leucine Zipper, Nucleosome, Zipper
Document Summary
Eukaryotic gene expression is usually controlled at the level of initiation of transcription by opening the chromatin. Insulators can block the spreading of chromatin modifications from one domain to another: mechanism of action of activators and repressors. Work by making protein-protein contracts with basal factors. Activators are regulated in many different ways. Antirepressor- a positive regulator that functions in opening chromatin. Repressor- a protein that inhibits expression of a gene. It may act to prevent transcription by binding to an operator site in dna or to prevent translation by binding to rna. Positive control- the default state of genes that are under positive control is that they cannot be expressed unless a positive regulator is bound. Architectural protein- a protein that, when bound to dna, can alter its structure. Negative control- the default state of genes that are under negative control is to be expressed. A specific intervention is required to turn them off.
