midterm 2-book - Sigma factor: a protein needed for...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Sigma factor : a protein needed for initiation of RNA synthesis, not for its elongation. Help core RNA polymerase locate consensus promoter sequences near the beginning of a gene. -10 and -35 bp upstream of the transcription start site. (E.Coli) Promotor : a specific DNA sequence which signals the beginning of a gene. Consensus sequence: The DNA sequence similarities seen when comparing these different promoters define a consensus sequence likely recognized by the sigma factor. A consensus sequence consist of the most likely bases at each position of the predicted promoter. Dynamic changes in gene expression result when the relative levels of different sigma factors change. Transcription initiation graph: 1. RNA polymerase holoenzyme scans DNA for promoter sequences. 2a. Binding to the promoter sequence forms the closed complex. 2b. The antibiotic rifamycin will bind to this form of polymerase and prevent formation of the subsequent open complex.3a. RNA polymerase unwinds DNA and begins transcribing RNA from ribonucleoside
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

midterm 2-book - Sigma factor: a protein needed for...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online