Talk abstracts
Talk on Saturday 08:45-09:00am submitted by Morgan Shine
Gradual and sudden heat exposure induce distinct alternative splicing programs in green algae
Morgan Shine (Department of Molecular Biophysics and Biochemistry, Yale University), Karla M. Neugebauer (Department of Molecular Biophysics and Biochemistry, Yale University)
Abstract:
Microalgae serve a fundamental role in the environment as primary producers, acting as a major food source for other organisms and producing about half of the oxygen in the atmosphere. Aquatic heatwaves are becoming more frequent and severe, making it critical to understand the microalgal heat stress response. Alternative splicing (AS), in which multiple messenger RNA (mRNA) isoforms are generated from a single gene, can equip organisms with molecular tools to combat stress. In this study, we profiled the AS landscape of the freshwater microalga Chlamydomonas reinhardtii in response to heat stress using short-read and long-read RNA sequencing. Algae were exposed to heat stress at 37C either suddenly (heat shock, HS) or gradually (gradual warming, GW) over the course of one day, and transcriptional signatures that were unique or shared between HS and GW were identified. We found 1,170 heat-induced AS events across 717 genes, including many kinases and RNA-binding proteins that could serve regulatory roles. Notably, 363 of these events required gradual warming for their expression at 37C. Most heat-induced AS events occurred in distinct isoforms rather than being coordinated within the same isoforms and were unique to the heat stress response compared to cold, osmotic, and nutrient stress. Many of these events were also predicted to add or remove short sequences (~22 amino acids) or introduce premature termination codons (PTCs). Our work suggests that transcripts with heat-induced PTCs evade degradation by nonsense-mediated decay. Overall, our findings suggest that RNA-based regulation underlies microalgal responses to changing environmental conditions.
Keywords: Alternative Splicing, Heat Stress, Algae