Identification and Characterization of Novel snRNA Processing Regulators in C. elegans
Date
2024-12-16
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Journal Title
Journal ISSN
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Publisher
ORCID
Type
Thesis
Degree Level
Doctoral
Abstract
Splicing of messenger RNA is a hallmark of eukaryotic cells. snRNA molecules are critical for precise splicing as they recognize and target the spliceosome to specific sequences of precursor mRNA that require splicing. The Integrator complex has been implicated in the processing and maturation of these snRNA molecules. Perturbations to splicing can have deleterious consequences, leading to various human diseases including cancer. Using the model organism C. elegans I identified several novel snRNA processing regulators. In Chapter 2, using a reverse genetic screen I found that the Argonaute CSR-1 plays a pivotal role in snRNA processing. Loss of CSR-1 caused increased levels of snRNA misprocessing that was dependent on the catalytic activity of the CSR-1b isoform. RNA-seq studies revealed the transcriptome is altered similarly during both CSR-1 or INTS-4 knockdown, indicating these proteins affect similar biological pathways. Additionally, members of the nuclear pore complex NPP-1, NPP-3, and NPP-6 were also confirmed to cause snRNA misprocessing through qPCR analysis. In Chapter 3 I isolated additional snRNA processing regulators through a forward genetic screen and determined to which degree they cause misprocessing. SNP mapping identified mutations in rde-11, rde-1, sago-2, and rsd-2, all components of the RNAi pathway, causing snRNA misprocessing. Complementation analysis confirmed the identified mutations were causing the misprocessing defect. Finally, in Chapter 3, I examined the effects these novel regulators have on maintaining a normal lifespan. The catalytic activity of CSR-1b was found to be essential in promoting a healthy lifespan. Depletion of any of the RNAi components identified in Chapter 2 all caused decreases in average lifespan, as did the majority of nuclear pore proteins. Overall these results highlight the importance of transcriptome regulation and integrity in maintaining a healthy lifespan.
Description
Keywords
Development
Aging
Cell biology
Genetics
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Veterinary Biomedical Sciences
Program
Biology