Belmont University Research Symposium (BURS)

Publication Date

Spring 4-18-2024

College

Sciences and Mathematics, College of

Department

Biology, Department of

BURS Faculty Advisor

Rebecca Adams

Presentation Type

Poster Presentation

Abstract

Gene expression is essential to life and occurs through the processes of transcription of mRNA in the nucleus, export of transcripts to the cytoplasm through the nuclear pore complex (NPC), and translation of the mRNA into protein in the cytosol. This process is highly conserved and tightly regulated, and in this study, the budding yeast S. cerevisiae serves a eukaryotic model system used to explore the regulation of mRNA export. Under ideal growth conditions, transcripts are able to exit the nucleus through interaction with Mex67 which binds mRNA via RNA-binding adaptor proteins and allows crossing through NPCs. However, during cellular stress, including heat shock (42°C), known adaptor proteins are rendered dysfunctional, thus halting general mRNA export. However, under these conditions, specific stress-induced transcripts retain the ability to exit the nucleus to enable the cell to response to stress. For example, the SSA4 transcript encodes a chaperone that helps denatured proteins refold following heat shock, is able to selectively export in response to stress. The mechanism for this selective export of SSA4 is not understood. I hypothesize that an unknown adaptor protein recruits Mex67 to allow for its selective export from the nucleus. Our overarching goal has been to identify this adaptor via a genetic screen. To enable this, my goal has been to generate phenotypic reporters that yield a color change in response to stress conditions. Specifically, I have used CRISPR to integrate the LacZ ORF into the endogenous SSA4 genetic locus to retain SSA4 regulatory sequence. We anticipated that these reporters would yield blue yeast cells if selectively exported during heat shock conditions. Future analysis will test whether these reporters successfully recapitulate selective SSA expression and export and use of these reporters for genetic screening to identify proteins involved in selective mRNA export.

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