Coordinated regulation of gene expression by E ... - Jacobs University
Coordinated regulation of gene expression by E ... - Jacobs University
Coordinated regulation of gene expression by E ... - Jacobs University
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RESULTS<br />
contrast the tyrTD promoter mutant showed significantly increased reactivity within the<br />
−10 region at positions T-8, A-10, T-11 and A-12 (lanes 4, 5). In addition bases T-3 and<br />
T-4 within the discriminator as well as bases T+3 and T+4 were reactive suggesting that<br />
DNA unwinding had extended from the −10 region to the start point in this mutant. No<br />
enhanced signals were observed in the other mutants in these positions (C-3, C-4). For<br />
both the tyrTS and tyrT35U increased reactivity was observed within the −10 region at<br />
positions T-8, A-10, T-11 and A-12 (lanes 7, 8 and 10, 11) although the effect was<br />
much for the former mutant. Unlike the tyrTD mutant neither <strong>of</strong> the tyrTS nor the<br />
tyrT35U mutant promoters exhibited increased reactivity at positions T+3, T+4.<br />
Figure 21: Potassium permanganate footprinting <strong>of</strong> ptyrT and its derivatives.<br />
(A) Footprinting performed in the absence <strong>of</strong> nucleoside triphosphates. The positions <strong>of</strong> permanganate<br />
reactive thymine bases are indicated. (B) Footprinting performed in the presence <strong>of</strong> initiating nucleoside<br />
triphosphates GTP and CTP. FIS and RNAP when added is indicated <strong>by</strong> a ‘+’. Wt, D, S and 35U are the<br />
wild-type and mutants <strong>of</strong> ptyrT.<br />
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