Introduction
The purpose of this project was to study the transcriptome of Saccharomyces
cerevisiae ΔZMS1 (ΔRSF2) using microarray technology as a
collaborative project with
Dr. Kim Slekar of
James Madison University’s
Biology Department investigating genes in S. cerevisiae
functionally related to ΔZWF1. S. cerevisiae, commonly
referred to as baker’s yeast is a single-celled eukaryote which is used as a
model system for eukaryotic organisms as it can easily be genetically
manipulated and its genome has been sequenced. S. cerevisiae
is a facultative anaerobe and therefore
has cellular anti-oxidant factors to allow it to survive in the presence of
oxygen (Rosenfeld and Beauvoit, 2003). Oxygen creates reactive oxygen species such as hydrogen peroxide, superoxide anions, and hydroxyl radicals. These reactive oxygen species cause
cellular damage such as DNA strand breaks, damage to essential enzymes and
proteins, and damage to cell membranes. Oxidative stress is also linked to
diseases in humans such as neurodegenerative disease, cancer, and cardiovascular
disease. Examples of cellular anti-oxidant factors include superoxide dismutase,
catalase,
glutathione peroxidase, thioredoxin, and glucose 6-phosphate
dehydrogenase (G6PD). Dr. Slekar’s research studies ΔZWF1 which encodes
for G6PD in S. cerevisiae and has shown that the phenotype of S.
cerevisiae ΔZWF1 is sensitive to oxygen and thus sensitive to
oxidizing agents (Slekar et al. 1996). This led Dr. Slekar into investigating genes in S.
cerevisiae functionally related to ΔZWF1. A multi-copy suppressor of
the ΔZWF1 phenotype is ZMS1 which is referred to as RSF2 in
the database. Due to Dr. Slekar’s research referring to this gene as ZMS1,
this project will also refer to this gene as ZMS1 instead of RSF2. Extra
copies of the ZMS1 gene added to S. cerevisiae ΔZWF1
suppress the deletion and restore the phenotype to wild-type. Also, ZMS1
appears to encode a potential zinc-finger transcription factor which may govern
the expression of some mitochondrial genes and many nuclear genes (Lu et al,
2005). As an attempt
to better understand ZMS1’s role in oxidative stress in S. cerevisiae,
this project used microarray technology to study the transcriptome of S.
cerevisiae ΔZMS1. Microarrays are useful tools for this
kind of study because they allow the investigation of the entire genome whereas
more common methods can only look at a few genes at a time (DeRisi et al.
1997). Due to this more thorough approach, unknown genes may be
discovered, and/or new information for some genes can be inferred through
apparent association with known genes from known pathways. For a flash animation detailing how the procedure
of performing a microarray study is carried out please visit this
website provided by
Davidson College’s
Biology Department. Due to ZMS1 being knocked out of S.
cerevisiae for this microarray study, it was hypothesized that gene
expression differences would be observed in genes involving transcription
factors related to oxidative stress when compared between the ΔZMS1 and
the wild type.
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