BI236 Lecture 13: BI236 – Gene Expression 3
Document Summary
Enhancers and silencers: sequences associated with the promoter, located at variable distances from the promoter, contain sequences that are bound by regulatory proteins (transcription factors, they act from a distance via dna loops and protein intermediaries. Distance relative to promoter can vary greatly: enhancers - stimulate gene expression. Regulatory transcription factors binds to enhancers are activators: silencers - inhibit gene expression. Regulatory transcription factors binds to silencers are repressors: looping - brings enhancer closer to core promoter. Interaction between enhancers and the genes they regulate. Two basic principles govern the interaction between enhancers and the genes they regulate. Coactivator proteins - mediate the interaction between activators and rna polymerase complex bound to core promoter. Eg. enzyme histone acetyltransferase (hat) a coactivator that adds acetyl groups to histone molecules and thereby promotes chromatin decondensation. Another group of coactivators involved in chromatin remodelling (altering chromatin structure) swi/snf family of coactivators.
