Magnesium regulates transcription of the mgtA (magnesium transporter) gene in Salmonella enterica serovar typhimurium via prolyl-bond formation during translation of the mgtL leader ORF

<p>In <em>Enterobacteriaceae,</em> the <em>mgtA</em> gene encodes a P-type ATPase that mediates Mg2+ uptake and is up-regulated by the PhoQP two-component system during invasion of host epithelial cells and macrophages. The regulation of <em>mgtA</em> has recently gained special interest given that it exists at several stages, including transcription, post-transcription and post-translation, in response to Mg2+availability. The <em>mgtA</em> mRNA has a 264-nucleotide 5’ leader that contains a 17 codon, proline-rich ORF, termed <em>mgtL,</em> whose translation has been proposed to affect the folding of the 5’ leader mRNA, which in turn regulates whether transcription is terminated before the <em>mgtA</em> structural gene at high Mg2+ concentrations, or is allowed to read through at limiting Mg2+ concentrations. We hypothesize that Mg2+ directly regulates translation of <em>mgtL</em> by facilitating prolyl-bond formation. We find that rescue of ribosome stalling at proline codons of <em>mgtL</em> by translation factor EF-P and methylation of tRNAPro with m1G37 by TrmD both play roles in the regulation of <em>mgtL</em>translation. Of potential significance is that TrmD is dependent on Mg2+ for its tRNA methylation activity, implying an underlying role of Mg 2+ in the regulation. We suggest a complex interaction between Mg 2+, proline, EF-P and TrmD in the regulation of <em>mgtL</em> translation and <em>mgtA</em> transcription. In addition, we provide preliminary results implicating an unknown transcription factor and other potential growth conditions in the regulation of <em>mgtA</em> expression.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biological Science

Year

2016

Author dc:creator

• Gall, Aaron R

Contributors dc:contributor

• Laszlo Csonka
• John Anderson
• Bruce Applegate
• Michael Gribskov

• Biological sciences
• Enterobacteriaceae
• Magnesium
• Magnesium Transporter
• mgtA
• mgtL
• Microbiology

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/648

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-1766