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Mol. Cells 2008; 26(2): 212-215

Published online August 31, 2008

© The Korean Society for Molecular and Cellular Biology

Effects of Base Changes at the Transcription Start Site on Stringent Control of rnpB in Escherichia coli

Hyun-Sook Choi, Jeong Won Park, Soon Kang Hong, Kangseok Lee and Younghoon Lee

Abstract

The GC-rich discriminator sequence between the -10 region and the transcription start site of the rnpB promoter is responsible for stringent control of M1 RNA synthesis. The rnpB promoter also contains a G nucleotide at the previously identified transcription start site. In this study, we examined by mutagenesis of G to A whether this +1G nucleotide is involved in the stringent response. We found that the change did not alter the stringent response. Since the +1 mutation might alter transcription initiation, we compared the transcription start sites of the wt and mutant promoters by primer extension analysis. Surprisingly, we found that wild type rnpB transcription starts at both the +1G position (70%) and the -1C position (30%), and that the +1A mutation led to transcription initiation exclusively at the -1C position. We also generated two transversion mutations at the -1 position, both of which led to transcription starting exclusively at that position. The -1G mutant promoter gave a stringent signal similar to the wild-type, whereas the -1A mutant generated a significantly less stringent signal. Base on these results, we propose that a short sequence, up to 7 bp downstream of the -10 region, is involved in the stringent response of the rnpB promoter.

Keywords -10 region, discriminator, Escherichia coli, M1 RNA, mutation, rnpB, stringent control, transcription, transcription start site

Article

Communication

Mol. Cells 2008; 26(2): 212-215

Published online August 31, 2008

Copyright © The Korean Society for Molecular and Cellular Biology.

Effects of Base Changes at the Transcription Start Site on Stringent Control of rnpB in Escherichia coli

Hyun-Sook Choi, Jeong Won Park, Soon Kang Hong, Kangseok Lee and Younghoon Lee

Abstract

The GC-rich discriminator sequence between the -10 region and the transcription start site of the rnpB promoter is responsible for stringent control of M1 RNA synthesis. The rnpB promoter also contains a G nucleotide at the previously identified transcription start site. In this study, we examined by mutagenesis of G to A whether this +1G nucleotide is involved in the stringent response. We found that the change did not alter the stringent response. Since the +1 mutation might alter transcription initiation, we compared the transcription start sites of the wt and mutant promoters by primer extension analysis. Surprisingly, we found that wild type rnpB transcription starts at both the +1G position (70%) and the -1C position (30%), and that the +1A mutation led to transcription initiation exclusively at the -1C position. We also generated two transversion mutations at the -1 position, both of which led to transcription starting exclusively at that position. The -1G mutant promoter gave a stringent signal similar to the wild-type, whereas the -1A mutant generated a significantly less stringent signal. Base on these results, we propose that a short sequence, up to 7 bp downstream of the -10 region, is involved in the stringent response of the rnpB promoter.

Keywords: -10 region, discriminator, Escherichia coli, M1 RNA, mutation, rnpB, stringent control, transcription, transcription start site

Mol. Cells
Nov 30, 2022 Vol.45 No.11, pp. 763~867
COVER PICTURE
Naive (cyan) and axotomized (magenta) retinal ganglion cell axons in Xenopus tropicalis (Choi et al., pp. 846-854).

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