BIOB11H3 Lecture Notes - Lecture 5: Precursor Mrna, U2Af2, Nucleic Acid Sequence
Document Summary
Lec 5: rna splicing (rna splicing and related phenomena) Found ciliated protozoan (tetrahymena) synthesized an rrna precursor (pre-rrna) that was capable of splicing itself. Intron in the tetrahymena pre-rrna is a group 1 intron. Another type of self-splicing intron called group 2 intron found in fungal mitochondria, plant chloroplasts, and variety of bacteria. Group 2 introns fold into a complex structure. Removal of intron in pre-mrna is different from group 2 introns because pre-mrna can"t splice itself. Requires host of small nuclear rnas (snrnas) and their associated proteins. As hnrna mol is transcribed becomes associated w/ variety of proteins = heterogeneous nuclear ribonucleoprotein (hnrnps) = substrate for the processing reactions that follow. Each intron of pre-mrna associates with a spliceosome. Spliceosome consists of a variety of proteins + distinct ribonucleoprotein particles small nuclear ribonucleoproteins (snrnps) Spliceosomes are not in an assembled state when in the nucleus. They are assembled when the snrnps in them bind to the pre-mrna.
