Skip navigation
Please use this identifier to cite or link to this item: http://arks.princeton.edu/ark:/88435/dsp013j333456s
Title: sRNA Regulation within the Cpx Stress Response Pathway
Authors: Koren, Daria
Advisors: Silhavy, Thomas
Department: Molecular Biology
Class Year: 2015
Abstract: The Cpx pathway of Escherichia coli contains a two-component stress response system that combats many extra-cytoplasmic toxicities, such as misfolded P-pilus (Pap) proteins. Pap proteins are essential for adhesion in uropathogenic E. coli and are prone to misfolding. The sensing domain histidine kinase CpxA is attached at the inner membrane, phosphorylating the response regulator domain CpxR. CpxR then affects many gene targets within the regulon. CpxP, one of the most regulated protein products of the Cpx regulon, appears to have several jobs within the stress-combative cascade. The periplasmic protein has a signal sequence that directs secretion from the cytoplasm before being cleaved; the mature CpxP acts negatively upon CpxA stimulation, reducing its own transcription, in addition to binding to the misfolded proteins to help attract proteases to degrade offending Pap subunits. In addition, a 3‟ untranslated region (UTR) has been found to produce an sRNA for CpxP. We demonstrate that this cpxP 3‟ UTR, CPxQ, decreases CpxP protein levels; the native CpxP signal sequence is necessary for this post-transcriptional regulation to occur. Specifically, the mechanism by which CpxQ affects CpxP production is still unclear; broadly, the effects of the post-transcriptional regulation are uncharacterized within the Cpx pathway. Additionally, we find that deletion of the CpxQ reverses a constitutively active mutation of CpxA and hinders stress alleviation in the periplasm. Therefore, we suggest the model that CpxP is the harbinger protein of the negative feedback mechanism for the Cpx stress response pathway, while CpxQ acts like a riboswitch.
Extent: 49 pages
URI: http://arks.princeton.edu/ark:/88435/dsp013j333456s
Type of Material: Princeton University Senior Theses
Language: en_US
Appears in Collections:Molecular Biology, 1954-2016

Files in This Item:
File SizeFormat 
PUTheses2015-Koren_Daria.pdf787.78 kBAdobe PDF    Request a copy


Items in Dataspace are protected by copyright, with all rights reserved, unless otherwise indicated.