BIO206H5 Lecture Notes - Lecture 10: Exon Junction Complex, Rna Splicing, Nuclear Pore
Document Summary
Associated with 4 areas of chromosomes (they need to be all in place before polymerase can begin transcription) Rna splicing: intron removal introns removed & exons spliced together requires small nuclear ribonucleoprotein particles (snrnps - snurps ) = proteins + snrnas. Collectively: complex of snurps = spliceosome occurs in nucleus after capping and before tailing incompletely processed mrnas are not exported from nucleus. Introns need to be physically removed, exons need to be spliced together (done by spliceosome) An assembly of 5 snrnps complexes small nuclear ribonuclearproteins (snurp) snrnp u1 = proteins + snrna u1 small nuclear rna (snrna) - 5 snrna + more than 60 polypeptides. Note how u2 binds to the 2 bases on either side of the branch point adenosine & leaves that one sticking out. U1 has complimentary sequence to 5" splice site. Sr proteins are serine arginine rich proteins that bind to rna.
