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> Home > Faculty
& Staff > Dr. Mensur Dlakic
Our understanding of Archaea as a third domain of life is incomplete because
of their relatively recent discovery. Archaea are often found in extreme environments
and provide good model systems for understanding the adaptations needed to
sustain life in such conditions. The viruses that replicate in thermophilic
Archaea have been studied recently in an attempt to understand the biochemistry
and molecular biology of their hosts. Using advanced tools of bioinformatics,
our lab has tentatively assigned functions to about one third of proteins found
in Fuselloviridae isolated from Sulfolobus species. Somewhat
surprisingly, almost 20% of viral open reading frames are predicted to code
for DNA-binding proteins. This finding strongly implies that the viruses have
developed mechanisms for tight regulation of their own transcription, and possibly
that of their hosts. Our goal is to characterize these proteins in order to
increase our understanding of the mechanisms of transcriptional regulation
in these viruses and their hosts.
We found that Sulfolobus spindle-shaped viruses (SSVs) code for ribbon-helix-helix
(RHH), winged helix-turn-helix (wHTH) and zinc-finger DNA-binding proteins.
Interestingly, at least one protein from each of the three groups of DNA-binding
proteins is shared between all four SSV species, clearly indicating common
functions for these proteins in all SSVs. We are in the process of cloning
these proteins to test them in gel-shift and in vitro selection experiments.
We expect that these experiments will provide insights about the distribution
of DNA binding sites in viral and host genomes. A long-term goal of this work,
and a likely direct outcome of the experimental results obtained, will be greater
understanding of transcriptional regulation by DNA-binding proteins of SSVs.
There are several important questions to be answered after the initial data
are obtained as part of this proposal: 1) What are the effects of expression
of these proteins on transcription in both viral and host genomes? 2) If one
or more of these proteins are transcriptional repressors, what is the trigger
for de-repression? 3) What is the molecular nature of the de-repression mechanism?
Our results are likely to converge with other research groups interested in
thermophilic viruses at Montana State University and will provide more detailed
picture of viral and host transcriptional regulation.
Current Lab Personnel:
Cathy Castle, M.S. Student
Joella Geary, M.S. Student
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