| dc.description.abstract | RNA splicing, an important co-transcriptional change in many eukaryotes, involves processing pre-mRNA before it exits the nucleus to either translate into proteins or function as RNA. This splicing crucially includes removing introns, where the accurate identification of specific nucleotide sequences is vital. Key signals are located at the introns’ 5' and 3' ends as well as within the intron itself. Branch points are such specific sequences within the intron of a gene that play a crucial role in the splicing of pre-mRNA. The branch point is a critical component of the splicing machinery, typically consisting of an adenine nucleotide that acts as the attack site for the first step of splicing. This site is located upstream of the intron's 3' splice site and is part of a larger sequence that is recognized and bound by splicing factors. The branch point, along with other elements such as the 5' splice site, the polypyrimidine tract, and the 3' splice site, forms a complex with the spliceosome, a large RNA-protein complex responsible for carrying out the splicing process. The spliceosome binds these signals, triggering an intramolecular change to form a lariat structure. Errors in this identification can cause significant shifts in protein synthesis and function. In Caenorhabditis elegans, a nematode and model organism in molecular biology, the 3' and 5' splice sites are well-defined, as seen from yeast to mammals, but its branch point sequence remains unknown. Understanding RNA splicing in C. elegans, particularly regarding the branch point, is the focus of this project. Our research aims to characterize separate branch points and understand whether a branch point consensus exists in the introns of C. elegans. We identified several branch points and the most common one was typically an adenine nucleotide located 31 to 15 nucleotides upstream of the 3' splice site, with an average position of 20 nucleotides from the 3' splice site. This spatial arrangement of the branch point is consistent with patterns seen in other species, such as yeast and mammals, indicating a possible conserved structural feature in different life forms. In C. elegans, the branch point is usually preceded by cytosine and followed by adenine or uracil, while cytosines or guanines are often absent from the branch point position. | |
