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Unformatted text preview: e 5' side of the lacZ gene of E. coli.
Some of these mutations resulted in a decrease in lac mRNA and were
therefore called "down promoter mutations." Our first impressions of
the physical structure of the promoter came in 1975 when David
Pribnow sequenced RNAP-protected DNA fragments to define the size
and nucleotide sequence of the three bacteriophage T7 promoters.
RNAP was bound to the T7 promoters and locked down with the
dinucleotide T7 DNA RNAP
5’pppGpA BIS101001, Spring 2013—Genes andGene Expression, R.L. Rodriguez ©2013
BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 18 Promoter Structure: The Pribnow Experiment DNase was added to the T7 DNA and small DNA fragments (RNAP
protected DNA) were produced. The RNAP was striped with phenol,
cleaned and sequenced.
cleaned Pribnow identified three conserved sequences with fairly fixed spacing;
(1) -35 region, (2) the -10 or Pribnow box; and (3) the +1, the initiation
DNase GTTACA -35 TATPuATG Pu -10 +1 BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013
BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez +18 19 The Consensus Promoter
The Hundreds of prokaryotic promoters have since been sequenced and found to have
highly conserved regions that correspond to Pribnow's consensus +1, -10 and -35
sequences. This has led to the concept of a consensus promoter sequence (Fig.
8-12). A consensus promoter sequence is a hypothetical sequence based on the
most commonly occurring nucleotides at a particular position. BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013
BIS101001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 20 Consensus Promoters and Mutations In the sequence shown below, upper and lower case letters repr...
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This note was uploaded on 02/12/2014 for the course BIS 101 taught by Professor Simonchan during the Spring '08 term at UC Davis.
- Spring '08