Sanat Myti / Chemistry & Biochemistry / Faculty Mentor: Byung Ran So
Ribonucleoprotein complexes play a crucial role in post-transcriptional gene expression. Spliceosome is a macromolecular RNA:Protein (RNP) complex that facilitates splicing, producing full-length messenger RNAs. Comprising five small nuclear ribonucleoproteins (snRNPs) and over fifty splicing factors, this machinery organizes the assembly and catalysis required for the conversion of premature mRNA into mature forms. While the spliceosomes require equal stoichiometry of snRNPs for splicing, the abundance of snRNP varies significantly in a tissue- and development-specific manner. However, the molecular mechanisms by which cells regulate snRNP abundance and its repertoire remain poorly understood. This process involves the SMN complex, a multi-component RNP chaperone responsible for assembling a Sm core on each snRNA and ensuring the stability snRNPs. Here, we examined the snRNP code and identified interactions between snRNP-specific proteins and the SMN complex. We measured the in vitro Sm core assembly activity on snRNAs and the abundance of native snRNPs in HeLa cells with snRNP-specific protein knockdown by siRNA transfection. Our findings reveal that some snRNP-specific proteins not only reduced canonical snRNP assembly, but also enhanced others. These results suggest that snRNP-specific proteins play a role in regulating snRNP abundance by either promoting snRNP assembly or stabilizing snRNPs, mediated by the SMN complex.
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