BISC401 Lecture Notes - Lecture 12: Sr Protein, Rna Splicing, Snrnp
2 Nov 2016
School
Department
Course
Professor
Document Summary
Snrna in snrnps base pair with pre-mrna during splicing. Five u-rich snrnas (u1, u2, u4, u5, u6) participate in pre-mrna splicing: ranging in lenth from 107-210 nucleotides, 6-10 proteins associated with each snrna. Average length of an exon is the human genome is about 150bases. Average length of an intron is about 3500 bases. A family of rna-binding proteins, the sr proteins, interact with sequences within exons called exonic splicing enhancers. Sr proteins contain several protein-protein interaction domains rich in arginine (r) and serine (s) residues, called rs domains. When bound to exonic splicing enhancers, sr proteins mediate the cooperative binding of u1 snrnp to a true 5" splice site and u2 snrnp to a branch point through a network of protein-protein interactions that span an exon. The complex of sr proteins, snrnps, and other splicing factors that assemble across an exon, which has been called a cross-exon recognition complex, permits precise specification of exons in long pre-mrnas.
