GOAL: To research the regulatory pathways
for the genes that expresses pili in Geobacter
sulfurreducens.
1. Abstract
(proposed)
To determine the
regulatory pathway and external factors that controls production of type IV
pili in Geobacter sulfurreducens. Geobacter sulfurreducens is a bacterium that can produce
electricity and precipitates solid metals. It contains type IV pili, which are the proposed mechanism
that allows G. sulfurreducens to
attach directly to Fe(III) oxide surfaces. The gene PilA codes for type IV pili in Gram-negative
bacteria. A “Two-component
regulatory system” regulates PilA.
In a two-component system, proteins sense then respond to
environmental changes. The sensor
protein is a histidine kinase (HK) and the response regulator (RR) protein
contains a phosphoryl group. Once
activated the RR can then effect changes in cellular physiology by regulating
gene expression.
The proposed two-component for G. sulfurreducens are PilS a sensory box histidine kinase (HK) located
on gene GSU1494 and PilR a sigma-54 dependent DNA-binding response
regulator (RR) located on gene GSU1495. The cascading signal from PilR activates RpoN a RNA
polymerase sigma-54 that in turn activates PilA, a type IV pilus assembly
protein.
 |
| Two-component pathway |
Type IV pili have been extensively studied in other
bacteria, but not Geobacter
sulfurreducens. An attempt
will be made to correlate studies, primarily with Pseudomonas aeruginosa, to help determine the factors that activate the two-component
system in G. sulfurreducens.
2. The goal of my BIO610 paper was to establish a
connection between OmcS and its involvement with the bacteria’s pili. The pili are needed for optimal
bacterial growth. This paper will
attempt to ascertain the factors that influence the cell’s pili production.
3. Areas that need improvement are writing in scientific
format, not using terms that are overly familiar and keeping the flow of
information organized to tell a coherent story.
4. References:
(Kanehisa_Laboratories). (2012). Two-component
system - Geobacter sulfurreducens. KEGG:
Kyoto Encyclopedia of Genes and Genomes. Retrieved from
http://www.genome.jp/kegg-bin/show_pathway?gsu02020+M00501
Leang, C., Krushkal, J., Ueki, T., Puljic, M.,
Sun, J., Juárez, K., Núñez, C., et al. (2009). Genome-wide analysis of the RpoN
regulon in Geobacter sulfurreducens. BMC
genomics, 10(Iii), 331.
doi:10.1186/1471-2164-10-331
Potvin, E., Sanschagrin, F., & Levesque, R.
C. (2008). Sigma factors in Pseudomonas aeruginosa. FEMS microbiology reviews, 32(1),
38-55. doi:10.1111/j.1574-6976.2007.00092.x
Sigma-Aldrich. (2012). Mucin. Sigma Aldrich Life Sciences. Retrieved
from
http://www.sigmaaldrich.com/life-science/metabolomics/enzyme-explorer/learning-center/structural-proteins/mucin.html
Tremblay, P.-L., Aklujkar, M., Leang, C., Nevin,
K. P., & Lovley, D. (2012). A genetic system for Geobacter metallireducens:
role of the flagellin and pilin in the reduction of Fe(III) oxide. Environmental Microbiology Reports, 4(1), 82-88.
doi:10.1111/j.1758-2229.2011.00305.x
UniPort. (2012). Two-component regulatory
system. UniPort, Keywords. Retrieved
from http://www.uniprot.org/keywords/902
You chose a very interesting topic. I wonder though, why did you pick pseudomonas aeruginosa to compare with your organism as opposed to other anaerobic gram negative bacteria? By the way, thank you for the information you gave me. (:
ReplyDeleteUnfortunately the information of PilA regulation is pretty scarce. I'm going to have to use whats available!
ReplyDeleteIt would be probably a good idea to explain it in the paper- we know that P. aeruginosa is a strictly oxidative bacterium, so there may be a similarity with Geobacter. Is Geobacter capable of fermentation, btw?
ReplyDelete