Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


MA-Formatted Thesis 12-1-16.pdf (1.09 MB)

ETD Abstract Container

Abstract Header

Identification of Factors Involved in the Regulation of the Bacillus subtilis metK Gene

Allen, George M
http://rave.ohiolink.edu/etdc/view?acc_num=osu1480616278645374

Abstract Details

2016, Master of Science, Ohio State University, Microbiology.
Riboswitches are cis-acting regulatory elements that respond to a variety of signals. The S box (SAM-I) riboswitches are S-adenosylmethionine (SAM)-responsive RNA regulatory elements located at the 5’ untranslated regions of genes involved in the biosynthesis and transport of methionine and SAM. Binding of SAM to the riboswitch RNA results in repression of downstream gene expression, primarily via transcriptional attenuation. The Bacillus subtilis metK gene, which encodes SAM synthetase, is an atypical member of the S box regulon. Unlike the other 10 S box regulated transcriptional units in B. subtilis, which are induced under methionine starvation conditions that result in low SAM levels, metK is expressed only when methionine concentrations are high and SAM concentrations are low. The metK leader region contains additional conserved sequences 5’ and 3’ of the S box riboswitch, designated the Upstream (US) and Downstream (DS) boxes, respectively. These sequences are highly conserved in Bacillales sp. The US and DS box elements were shown previously to base-pair in the absence of SAM. Extensive site-directed mutagenesis revealed a core region within the US and DS box elements that are sensitive to alterations in both sequence and base-pairing potential. Additionally, mutations in these sequences result in reduced transcript stability when methionine concentrations are high and SAM concentrations are low in vivo. We hypothesize that metK is regulated by two separate mechanisms. The S box riboswitch regulates expression by sensing the concentration of SAM to either allow transcription to occur when SAM pools are low or cause transcription termination when SAM pools are high. Regulation at the level of transcript stability is proposed to be mediated by an unknown trans-acting factor that binds to the base-paired US and DS boxes when methionine concentrations are high and SAM concentrations are low. In this study, two complementary approaches were employed to identify putative factors that interact with the US and DS boxes of the metK leader RNA. A genetic selection and screen was used to identify genes whose products are required for increased metK expression, and UV crosslinking was used to identify proteins that closely interacted with a shortened US-DS box RNA mimic.
Tina Henkin, Ph.D. (Advisor)
Irina Artsimovitch, Ph.D. (Committee Member)
Jane Jackman, Ph.D. (Committee Member)
Ruiz Natividad, Ph.D. (Committee Member)
52 p.
Microbiology
Riboswitch; S-adenosylmethionine; regulated mRNA stability; S box riboswitch

Recommended Citations

Citations

  • Allen, G. M. (2016). Identification of Factors Involved in the Regulation of the Bacillus subtilis metK Gene [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480616278645374

    APA Style (7th edition)

  • Allen, George. Identification of Factors Involved in the Regulation of the Bacillus subtilis metK Gene . 2016. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1480616278645374.

    MLA Style (8th edition)

  • Allen, George. "Identification of Factors Involved in the Regulation of the Bacillus subtilis metK Gene ." Master's thesis, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480616278645374

    Chicago Manual of Style (17th edition)

osu1480616278645374
235
© 2016, some rights reserved.Creative Commons License Identification of Factors Involved in the Regulation of the Bacillus subtilis metK Gene by George M Allen is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.