Poster abstracts

Poster number 19 submitted by Emily Slobodenyuk

Three genes, one protein: Investigating 3'UTR-driven mRNA localization and protein function of the calmodulin gene family

Emily Slobodenyuk (Cellular and Molecular Biology Program, University of Michigan), Kayla Lenshoek (Cellular and Molecular Biology Program, University of Michigan), Brittany Bowman (Department of Biological Chemistry, University of Michigan), Chase Weidmann (Department of Biological Chemistry, University of Michigan)

Abstract:
Calmodulin (CaM) is an essential, highly conserved, ubiquitously expressed calcium-binding protein, and interacts with many proteins to regulate processes including the cell cycle, neurotransmitter release, and the cardiac action potential. Interestingly, in mammals, three divergent CaM genes at separate genomic loci encode an identical calmodulin protein. Notably, the protein-coding regions of Calm1, Calm2, Calm3 mRNA within species are as minimally similar as possible while encoding the same protein sequence.
While encoding an identical protein, the individual Calm genes behave as though they are functionally distinct. All three Calm mRNAs are expressed in most cells, yet the levels of each Calm mRNA vary in different tissues and exhibit unique subcellular localization patterns. Identical mutations to the protein-coding sequences induce different disease phenotypes, depending on which Calm is affected. Further, Calm mRNA 3′UTRs (untranslated regions) are extremely different between the three genes yet are among the most conserved UTR sequences between the species. Since 3′UTRs are critical for regulating mRNA stability and localization, we expect that 3′UTR cis-regulatory elements drive the differential localization of the Calm transcripts and determine the distinct functions of each gene’s expressed CaM protein.
Through a combination of FISH reporter assays, epitope tagging, and affinity selection-mass spectrometry, we aim to understand how 3′UTR elements control the behavior of Calm mRNAs and the different encoded CaM protein interaction networks and functions. Neuronal cells provide a model for tracking localization of Calm mRNA and encoded protein in distinct cellular locales. I have begun by identifying Calm mRNA isoform distributions using short and long-read sequencing, and epitope-tagging the CaM protein products to track their distinct localization.

References:
Hanson et al., Neuron, 1994 ; Kahl et al., Endocr Rev., 2003; Villalobo, et al., Int J Mol Sci, 2020; Beghi et al., Int J Mol Sci, 2022; Gnegy et al., Brain Res, 1991; Munk et al., Cell Calcium, 2022; Toutenhoofd, et al., Cell Calcium, 2000; Innan et al, Nat Rev Genet., 2010; Palfi et al., J Histochem Cytochem, 1999; Palfi et al., Life Sci., 2002; Zhang et al., Neurosci., 1993; Bogdanov et al., Cardiovasc Res., 2025; Fischer et al., J Biol Chem., 1988; Siegfried et al., Nat Methods., 2014

Keywords: mRNA localization