[Determination of functional role of nucleotide composition in the transcription start region of the Escherichia coli udp gene].
The promoter of the Escherichia coli udp gene contains the poly-T (5'-TTTTT-3') motif in the transcription start region located at the distance of 3 nucleotides with respect to the Pribnow box. By means of site-directed mutagenesis, mutations in the +1, -1, and +3 positions of this region were isolated and their functional role in transcription initiation was determined. It was shown that in addition to the thymine nucleotide earlier identified at position 4 (with respect to the 5' end of the poly-T motif), the third thymine nucleotide may serve as an efficient transcription site. The functional significance of the presence of the poly-T motif in the transcription initiation region is discussed. Analysis of the isolated mutant promoters revealed the ability of the guanine nucleotide at the +3 position to stabilize the formation of a productive transcription complex and to serve as an additional transcription start.
State Research Institute of Genetics and Selection of Industrial Microorganisms, Moscow, 113545 Russia.
I V
IV
Ovcharova
S Iu
SIu
Eremina
A S
AS
Mironov
D001482:Base Composition; D001483:Base Sequence; D029968:Escherichia coli Proteins / Q000235:genetics*; D006147:Guanine; D008969:Molecular Sequence Data; D009154:Mutation; D011071:Poly T; D011401:Promoter Regions, Genetic; D012689:Sequence Homology, Nucleic Acid; D024363:Transcription Initiation Site; D001616:beta-Galactosidase / Q000235:genetics
D029968:Escherichia coli Proteins; C462660:udp protein, E coli; D011071:Poly T; D006147:Guanine; D001616:beta-Galactosidase