Global characterization of the Pho regulon in Caulobacter crescentus

Bacteria must sense and respond to their environment in order to survive and proliferate. Adapting to phosphate-limited conditions is particularly critical, as phosphate is a central component of many important biomolecules. Most bacteria respond to phosphate limitation through a widely conserved pathway, composed of the phosphate transport Pst system, and downstream signal transduction pathway, PhoR-PhoB, termed the Pho system. In this thesis, I use the model organism Caulobacter crescentus to characterize the response to phosphate limitation. I use ChIP-Seq on the transcriptional regulator PhoB to globally map the Pho regulon in Caulobacter in both phosphate-starved and -replete conditions. I find that the regulatory regions of over 50 genes are bound by PhoB following phosphate limitation, and I identify a consensus PhoB binding motif in Caulobacter. I then examine the function of PhoU, which is a putative negative regulator of the Pho regulon in Caulobacter and many other bacteria. I use morphological and microarray data to demonstrate that PhoU is not a negative regulator of the Pho regulon, and that it instead acts outside the PhoR-PhoB pathway. I find that the function of PhoU is tightly linked to cellular phosphate metabolism. This work offers insight into how Caulobacter responds to nutrient stress, as well as a better understanding of the connectivity and output of the phosphate limitation response pathway.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Biology.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2014

Author dc:creator

• Lubin, Emma A. (Emma Alexandra)

Advisor dc:contributor.advisor

• Michael T. Laub.

• Biology.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/87463

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/87463