GENE 320 Lecture Notes - Lecture 13: Aminoacyl Trna Synthetase, Rna Editing, Aminoacylation
Document Summary
Promoter -> transcription units (part of dna transcribed into rna) -> terminator. Transcription for each gene starts at the same site, the promoter. *most common/consensus sequence for e. coli promoters: -35 box (ttgaca), pribnow box (tataat). These are fairly conserved sequences - consensus shows strong promoters If it isn"t consensus they are slightly weaker promoters. Their conservation properties during evolution attests to the critical nature of their role in biological processes. (-35 & pribnow region (-10) ) Consensus sequences are nearly all the same (homologous) Sigma factors help the rna polymerase attach to speci c promoters is response to conditions. (heat shock, nitrogen starvation, phase infection, etc. ) Plays a regulatory function in the initiation of rna transcription. Several sigma factors help with gene expression within bacteria. Transcription: initiation begins - sigma binds to promoter region of dna, initiation continues - sigma opens the dna helix; transcription begins. Rna strand being made: initiation is complete - sigma releases; mrna synthesis continues.
