Stander Symposium abstract book - University of Dayton

POSTER SESSION 1
COLLEGE OF ARTS AND SCIENCES
A model to study the influence of Hippo signaling on local cell-cell interactions.
Presenter(s): Katelin E Hanes, Hailey Kwon, Alyssa C Lesko, Shilpi Verghese, Indrayani Waghmare
Advisor(s): Madhuri Kango-Singh, Amit Singh
Biology - Graduate Research
The Hippo pathway regulates organ size from flies to mammals. Molecular genetic approaches in Drosophila established the crucial foundation
of the mechanisms of signal transduction and function of the Hippo pathway. Recent studies uncover a role for Hippo pathway in phenomena
involving local cell-cell interactions like cell competition or compensatory proliferation. Hyperactivation of Yorkie (Yki) is crucial for compensatory
proliferation, cell competition,and regenerative growth. We have studied the micro-environment of scribble (scrib) mutant cells to gain insights
into the competitive ability of scrib mutant cells in the context of changes in Yki activity. scrib is a neoplastic tumor suppressor gene and loss of
scrib in homozygous larvae causes massive tumors to form. However, somatic clones comprising scrib mutant cells are slow growing and are competed
out by the surrounding wild-type cells by activation of JNK mediated apoptosis. We note that scrib mutant cells survive and proliferate when
additional mutations in scrib mutant cells either accelerate their proliferation or favor reduced cell competition (e.g., in Minute heterozygous
background). We found that JNK and Hippo signaling both play an important role in the growth and survival of scrib mutant cells. Furthermore,
activation of JNK can suppress the over-growth of Yki over-expressing cells. We decided tocompare the clone size and Hippo pathway read-outs
(ex-lacZ, diap1-lacz or diap-GFP) in five conditions viz., scrib-/-, scrib-/- M/+; scrib-/- + P35, wts-/- scrib-/- and RasV12 scrib-/-. Our preliminary
data shows that the interaction of scrib mutant cells with the surrounding wild type cells differ for each genotype. Here we present our analysis of
Yki activity in scrib mutant cells challenged with different cell competitive environments.
An evolutionary characterization of regulatory linkages in a genetic network for an
evolved fruit fly trait.
Presenter(s): John C Butts, Connor W McNamee
Advisor(s): Thomas M Williams
Biology - Graduate Research
Phenotypes are the culmination of spatial and temporal patterns of gene expression (protein production) for many genes comprising a genetic
network. These patters are controlled by cis-regulatory elements (CREs) and genes are connected into networks when a CRE regulating its expression
possesses binding sites for network transcription factor proteins - so called regulatory linkages. Gains and losses of linkages are a suspected
common route of CRE and network evolution; though, their emergence remains poorly understood as few case have revealed the before and after
states in sufficient detail. We study abdominal pigmentation of Sophophora fruit fly species, where male-specific pigmentation (e.g. Drosophila
melanogaster) evolved from a monomorphic ancestral state. A key modification to the pigmentation network was the evolved sexually dimorphic
expression of the Bab transcription factor proteins. These proteins turn off expression of the yellow and tan genes that are required for pigmentation.
The research presented here addresses two questions. First, does Bab form regulatory linkages with CREs that control the male-specific
expression of the Drosophila melanogaster yellow and tan genes? Second, when in the history of Sophophora were these CREs and their regulatory
linkages gained? To answer these questions we are: systematically mutating CRE sequences to find those needed to integrate the repressive
effects of Bab, and evaluating the regulatory activities of sequences related to the Drosophila melanogaster CREs. Future studies will explore
whether this divergence included the gain of Bab binding sites in dimorphic species or whether these binding sites were ancestral and conserved
during trait evolution.
Aquaglyceroporin expression and erythrocyte osmoregulation in cultures from freeze
tolerant anuran, Cope’s gray treefrog, Hyla chrysoscelis.
Presenter(s): Venkateshwar Mutyam
Advisor(s): Carissa M Krane
Biology - Graduate Research
Cope’s gray treefrog, Hyla chrysoscelis is a freeze tolerant anuran that accumulates glycerol during cold acclimation. We hypothesize that the
osmoregulatory capabilities of erythrocytes--to tolerate changes in cell volume and to affect rapid water and solute fluxes--are likely to be most
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