Thesis Defense Announcement
To: The George Mason University Community
*Candidate: Moushimi Amaya
Program: Master of Science in Biology
*Date: Thursday April 19, 2012
Time: 11:30 a.m.
Place: George Mason University, Prince William campus <http://www.gmu.edu/resources/visitors/findex.html>
Bull Run Hall, Room 247
*Thesis Chair: Dr. Monique van Hoek
Title: "THE PRENYLATION STATUS OF /FRANCISELLA/ /TULARENSIS /PROTEIN IN HUMAN CELLS"
A copy of the thesis is on reserve in the Johnson Center Library,
Fairfax campus. The thesis will not be read at the meeting, but should
be read in advance. All members of the George Mason University community
are invited to attend.
/Francisella tularensis/, the causative agent of tularemia, can
potentially be used as a bioweapon due to its highly infectious nature
and inhalation of as little as 10 organisms to cause onset of the
disease. As part of the infective cycle of /F. tularensis/, the
bacterium may release proteins into the cytoplasm of the host cell.
These proteins can be post translationally modified by the host cell
machinery. For example, a bacterial protein may be prenylated by the
host cell prenyltransferase. Prenylation requires the presence of a
CAAX motif on the C-terminal region of the target protein. A
bioinformatics program was used to predict /F. tularensis/ proteins that
are most likely to undergo prenylation. It was determined that only one
protein with a molecular mass of 13kDa and unknown function may be
prenylated. This study set out to experimentally determine the
prenylation state of this protein in human embryonic kidney cells.
Western blotting analyses indicated that the protein is indeed expressed
in transfected HEK293T cells. However, an immunoblot prepared to detect
prenylated proteins in cell lysates was unable to detect this protein.
The prenylation event was thus inconclusive. Protein fractionation
indicated that our protein of interest was primarily localized in the
cytosolic portion of transfected whole cell extracts. This suggested
that our protein was not prenylated. Growth assays of bacteria with
mutations in the genes were performed. However, independently, we
showed that this protein was not a required gene for intracellular
replication. Further analysis to elucidate the functionality of this
protein is required to deduce if this /Francisella/ protein could be a
candidate virulence gene.