SEPTEMBER 20 - Dr. Vikki Weake
Announcements
National FFA Convention- Thursday, October 25 - There are 4
time slots that are 50 minutes long (10am-3:50pm).
Email Gabe if you are interested in helping out at grangel@purude.edu.
Celebrate Science Indiana (CSI)- Saturday, October 6 - At the
Indianapolis Fairgrounds, at 8:30am-4pm.
There are rides available to the fairgrounds from campus, but you can
also meet us there if you live nearby.
Email Gabe if you are interested or have questions at grangel@purude.edu.
Old Business
The week of September 10-15, Biochemistry Club Outreach went
to Cumberland Elementary School, and had a great time.
The week of September 10-15, the grant for the Biochemistry
Club Outreach was turned in. We will
find out soon whether our grant was accepted.
New Business
T-shirt design has been made.
The shirts this year will have the saying “I
BCHM”, but the heart is a flask instead.
The shirts will cost around $8.
We will have more information next meeting.
Speaker- Dr. Vikki Weake
Novel Functions of Metazoan SAGA
Eukaryotic DNA is compacted into chromatin, which makes
chromosomes. Histones, which are
found on chromatins, are subjected to post-translation modification.
These modifications include acetylation, methylation, phosphorylation,
and ubiquitination (addition of small protein).
The modifications tell the cell what type of nucleosome it has.
Nucleosomes can be moved or displaced by chromatin remodelers.
Mutations of chromatin remodeling genes are found in cancer patients, so
correct chromatin remodeling is critically to human health.
Transcription factors, or activators, bind to specific DNA
sequences. They recruit
co-activators, or mediators, which in turn recruits the transcription machinery,
bringing in RNA polymerase I. SAGA
is a transcription co-activator, which is essential for viability in metazoans.
This means it plays critical roles in multicellular development.
SAGA is mis-regulated in cancer and neurodengative disease.
There are two histone modifications SAGA is involved in: acetylation
stimulates chromatin remolding, and ubiquition removal.
SAGA in fly vs. SAGA in yeast- To compare the SAGA, epitope-tagged
SAGA subunits were purified from cell cultures.
In yeast a subset of TAF proteins were found.
In Drosophila the SAGA contains other novel proteins, mainly 2 splicing
proteins.
SAGA in Neuron Cells vs. SAGA in Muscle Cells- There is tissue
specific expression of epitope-tagged SAGA.
The SAGA subunits all were present in the muscle and neuron cells.
SAGA binds to distinct genes in embryonic muscle and neuron (binds to
different genes). There is more
transcription factors present in SAGA from the muscle relative to neurons.
Glial cells are found in the brain, and are very important in
development. In SAGA mutations,
glial cells stop in the wrong place, and can cause vision defects.
This means that SAGA is associated with tissue-specific defects.