BIOLOGY 151 Lecture Notes - Lecture 19: Gel Electrophoresis, Matrox, Spliceosome
Document Summary
Alternative rna processing is extremely common in eukaryotic genes. Most genes produce multiple subtypes of mrnas that encode variants of the proteins encoded by the gene snrnps (small nuclear ribonucleoproteins) snrnps bind to the donor site, the branch site and acceptor site. First the cut the rna at the donor site. Then they form a lariat with a 5"-2" phosphodiester linkage with the a nucleotide in the branch site. Rna: the free 3" end of one exon attacks the 5" end of the other, the 3" and 5" ends of adjacent exons bond covalently, releasing the intron (which will then degrade) Large molecules get hung up in the matrix of the gel and travel slowly. In a given amount of time, they travel a shorter distance compared to smaller molecules that can travel through the gel matrox more easily. Donor and acceptor sites are both required for intron removal. Blocking the donor site, sprevents intron removal.
