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Negative and positive regulation of the non-osmoregulated ompS1 porin gene in Salmonella typhi : a novel regulatory mechanism that involves OmpR by Ricardo Oropeza; Clara Luz Sampieri; José Luis Puente; Edmundo Calva is a Biochemistry, Genetics and Molecular Biology article available to read on EtoBox.

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The __Salmonella typhi ompS1__ gene codes for an outer membrane protein of the OmpC/OmpF porin family. It is expressed at very low levels, relative to the major porins. However, deletion analysis of the 5′ regulatory region showed that the gradual removal of nucleotides −310 to −88, upstream from the P1 major transcriptional start‐point, resulted in a stepwise increase in expression, reaching levels 10‐fold above those for the __ompC__ major porin gene. Hence, this 222 bp segment contains __cis__‐acting regulatory elements involved in negative control. Primer extension analysis revealed the presence of three promoters: P1 activity was OmpR dependent; P2 was expressed at a lower level in the absence of OmpR; and P3 had a minor constitutive activity. OmpR bound preferentially to box II, an 18 bp F1/C1 canonical site, the removal (−88 to −66) of which resulted in a decrease in expression thus supporting its role in positive control. Expression of __ompS1__ was not induced by a set of stress conditions, including a shift in osmolarity, nor was the IHF regulator involved in negative control. An __ompS1__ homologue was found in __E. coli__ K‐12, which contains a nonsense codon and a shif

Who reads Negative and positive regulation of the non-osmoregulated ompS1 porin gene in Salmonella typhi : a novel regulatory mechanism that involves OmpR?

Author

Ricardo Oropeza; Clara Luz Sampieri; José Luis Puente; Edmundo Calva

Publisher

John Wiley and Sons; Wiley (Blackwell Publishing); Blackwell Publishing Inc.; Wiley (ISSN 0950-382X)

Published

1999

Language

EN

Field

Biochemistry, Genetics and Molecular Biology (Life Sciences)