The S. Typhi leuO gene contains multiple functional promoters
The S . Typhi leuO gene, which codes for the LysR-type transcriptional regulator LeuO, contains five forward promoters named P3, P1, P2, P5 and P4, and two reverse promoters, P6 and P7. The activity of the forward promoters was revealed by primer extension using gene reporter fusions in an S . Typhi...
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Published in | Journal of medical microbiology Vol. 70; no. 9 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
01.01.2021
|
Online Access | Get full text |
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Summary: | The
S
. Typhi
leuO
gene, which codes for the LysR-type transcriptional regulator LeuO, contains five forward promoters named P3, P1, P2, P5 and P4, and two reverse promoters, P6 and P7. The activity of the forward promoters was revealed by primer extension using gene reporter fusions in an
S
. Typhi
hns lrp
mutant strain. Likewise, the activity of the reverse promoters was revealed in an
hns
background. Derepression of the transcription of the chromosomal gene was confirmed by RT-PCR in the
hns lrp
mutant. The
leuO
P1 transcriptional reporter fusion, which contained only the major P1 promoter, had a lower expression in a
relA spoT
mutant strain, indicating that the steady-state levels of the (p)ppGpp alarmone positively regulate it. In contrast, the
leuO
P3,
leuO
P5P4,
leuO
P6 and
leuO
P7 transcriptional fusions were derepressed in the
relA spoT
background, indicating that the alarmone has a negative effect on their expression. Thus, the search for genetic regulators and environmental cues that would differentially derepress
leuO
gene expression by antagonizing the action of the H-NS and Lrp nucleoid-associated proteins, or that would fine-tune the expression of the various promoters, will further our understanding of the significance that multiple promoters have in the control of LeuO expression. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-2615 1473-5644 |
DOI: | 10.1099/jmm.0.001418 |