BIOL308 Lecture Notes - Rna Splicing, Snrnp, Cistron
16 Jul 2014
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Document Summary
Found mostly in protozoa and c. elegans mrnas are constructed by splicing or separate rna molecules, splicesome joins exon of one gene with the exon of another gene. Some messages are polycistronic units: this type of splicing enables creation of monocistronic mrna from polycistronic primary transcripts. Splicing of the mini exons with coding exons triggers polyadenylation of the 3" end. Mini exons will splice with 5" end exons of all protein coding transcripts contained in polycistronic primary transcript. One of several proteins from the u-snrnp complex: u1a. U1a protein can bind to two identical sites upstream of the poly (a) signal in its own pre -mrna autoregulation (pie) Binding will inhibit only polyadenylation and not cleavage mrna for the u1a protein is degraded. Co-ordinates expression of u1a with u1 snrnp assembly. Nuclear envelope is perforated by pores that can selectively transport macromolecules across the membrane (both direction)
