Matching Items (2)
Description
The Numb gene encodes an adaptor protein that has been shown to play a role in muscle repair, cell proliferation, and the determination of cell fate in satellite cells. Ablation of this gene in satellite cells results in an up-regulation of myostatin and p21, which inhibit the proliferation of myoblasts. These results indicate that the regulation of numb and myostatin could be used to amplify muscle regeneration. This would function as a therapeutic approach to degenerative muscle diseases, such as muscular dystrophy. There are four mammalian NUMB proteins produced through alternative splicing of the Numb mRNA transcript. Only two isoforms are present in adult mammalian muscle, indicating some form of muscle-specific post-transcriptional control of the gene. Additionally, the presence of two polyadenylation sites, and multiple miRNA seed sequences within the 3’ untranslated region (UTR) of mouse Numb indicate the possibility of regulation by a muscle specific miRNA.
ContributorsGefroh, Bailey Emelia (Co-author) / Gefroh, Bailey (Co-author) / Wilson-Rawls, Jeanne (Thesis director) / Rawls, Alan (Committee member) / Palade, Joanna (Committee member) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12
Description
Cleavage and polyadenylation is a step in mRNA processing in which the 3’UTR is cleaved and a polyA tail is added to create a final mature transcript. This process relies on RNA sequence elements that guide a large multimeric protein complex named the Cleavage and Polyadenylation Complex to dock on the 3’UTR and execute the cleavage reaction. Interactions of the complex with the RNA and specific dynamics of complex recruitment and formation still remain largely uncharacterized. In our lab we have identified an Adenosine residue as the nucleotide most often present at the cleavage site, although it is unclear whether this specific element is a required instructor of cleavage and polyadenylation. To address whether the Adenosine residue is necessary and sufficient for the cleavage and polyadenylation reaction, we mutated this nucleotide at the cleavage site in three C. elegans protein coding genes, forcing the expression of these wt and mutant 3’UTRs, and studied how the cleavage and polyadenylation machinery process these genes in vivo. We found that interrupting the wt sequence elements found at the cleavage site interferes with the cleavage and polyadenylation reaction, suggesting that the sequence close to the end of the transcript plays a role in modulating the site of the RNA cleavage. This activity is also gene-specific. Genes such as ges-1 showed little disruption in the cleavage of the transcript, with similar location occurring in both the wt and mutant 3’UTRs. On the other hand, mutation of the cleavage site in genes such as Y106G6H.9 caused the activation of new cryptic cleavage sites within the transcript. Taken together, my experiments suggest that the sequence elements at the cleavage site somehow participate in the reaction to guide the cleavage reaction to occur at an exact site. This work will help to better understand the mechanisms of transcription termination in vivo and will push forward research aimed to study post-transcriptional gene regulation in eukaryotes.
ContributorsSteber, Hannah Suzanne (Author) / Mangone, Marco (Thesis director) / Harris, Robin (Committee member) / LaBaer, Joshua (Committee member) / School of Life Sciences (Contributor, Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05