Abstract/Details

A novel sigma(E) regulated small RNA in Escherichia coli


2006 2006

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Abstract (summary)

The stationary phase and general stress alternative sigma factor σ S (RpoS) is regulated at multiple levels, including translational activation by two small regulatory RNAs. Out of a number of RNA modification mutants tested for a role in RpoS expression, a null mutation in miaA was shown to cause a defect in RpoS expression. Genetic experiments determined that MiaA is necessary for RpoS expression at the level of translation. In a separate portion of this work, the regulation of synthesis of the small RNA RybB was studied and found to be dependent upon the alternative sigma factor σE (RpoE). Increasing σE synthesis or activity led to a rapid and significant increase in the specific activity of a rybB-lacZ transcriptional fusion. Furthermore, both the activity of the rybB-lacZ fusion and the steady-state levels of the RybB RNA were undetectable in the absence of σ E. Genetic evidence suggested that RybB is only necessary for RpoS translation in the absence of RprA. To determine whether RprA affects rybB synthesis, the activity of the rybB-lacZ transcriptional fusion was measured in the absence of RprA and RybB. Surprisingly, the rybB-lacZ fusion increased only in the absence of RybB, suggesting that there is auto repression of RybB. This is the first demonstration of a σE regulated small RNA and adds a level of complexity to the σE regulon and the envelope stress response. This research also suggests that RybB and σE may be involved in an interesting auto-regulatory circuit.

Indexing (details)


Subject
Microbiology;
Molecular biology
Classification
0410: Microbiology
0307: Molecular biology
Identifier / keyword
Biological sciences; RpoS; RybB; Sigma E; Small RNA; Transcriptional fusion
Title
A novel sigma(E) regulated small RNA in Escherichia coli
Author
Thompson, Karl Manley
Number of pages
158
Publication year
2006
Degree date
2006
School code
0088
Source
DAI-B 67/09, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780542849237
University/institution
Howard University
University location
United States -- District of Columbia
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3230453
ProQuest document ID
305327154
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305327154
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