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Exploring a transcriptional regulation model governing a cis ‐antisense small RNA in Vibrio cholerae
Author(s) -
Zhang Mark Guangde,
Wang Jessica J.,
Lang Theodore,
Liu Jane M.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.525.9
Subject(s) - biology , vibrio cholerae , transcriptional regulation , mannitol , repressor , gene expression , regulation of gene expression , cholera toxin , microbiology and biotechnology , biochemistry , gene , genetics , bacteria
Cholera disease, a gastrointestinal ailment caused by the Gram‐negative bacterium Vibrio cholerae , remains a global health burden affecting an estimated 3–5 million people annually. V. cholerae's capacity to persist in different environments stems from its adaptability to a variety of sugar sources, including the six‐carbon sugar alcohol mannitol. Produced by algae metabolism, mannitol is transported into V. cholerae through the mannitol transporter MtlA, whose production is downregulated at the post‐transcriptional level by the small RNA (sRNA) MtlS. Currently, little is known surrounding what governs the transcription of mtlS , other than that mtlS expression is equally robust in non‐mannitol sugars. We examined the hypothesis that mtlS expression is subject to transcriptional interference from the divergently transcribed mtlA . Because MtlS is a cis ‐encoded sRNA transcribed directly antisense to mtlA , transcriptional activity from mtlA could pose a hindrance to mtlS transcription occurring in the opposite direction. To test this model, we grew V. cholerae in different sugar conditions and stimulated mtlA expression by knocking out mtlR (a transcriptional repressor of mtlA ) or by adding exogenous mannitol. We then measured MtlS sRNA levels by northern blot analysis. Our results indicate a strict inverse relationship between mtlA expression and mtlS expression, whereby the degree to which mtlA expression increases correlates with the extent to which mtlS expression decreases. In glucose, knocking out mtlR restores MtlA levels to 30% of maximum expression (n=3, p<0.05) and decreases MtlS levels by 33% (n=2, p=0.1). In non‐mannitol, non‐glucose sugars such as mannose, knocking out mtlR restores MtlA levels to 50% of maximum expression (n=3, p<0.05) and decreases MtlS levels by nearly 95% (n=3, p<0.01). These findings support a transcriptional regulation model regarding cis ‐antisense RNAs, known as the transcriptional interference model, for which there exist few characterized examples. Ultimately, this project has contributed to our understanding of how V. cholerae deploy sRNAs as an adaptive mechanism to buffer against environmental flux. Support or Funding Information NIH R15 AI090606 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .