BIOSC 1000 Lecture Notes - Lecture 23: Escherichia Coli, Polyadenylation, Cistron
Document Summary
Polycistronic: contains a promotor followed by a single protein coding sequence, promoter followed by multiple coding regions, transcribed into single mrna but translated into 3 separate protein, short regions of dna between coding regions contain instructions to halt translation, polycistronic genes that contain proteins involved in a single biochemical. Additional processing of rna mature mrna which is exported to the cytoplasm: sequences necessary for termination of transcription by rna polymerase, 5" cap, 3" poly a tail, covalent modification of nucleotides, polyadenylation at end. What about the other 98%: used to be caled "junk" dna, ~50% transcribed into non coding rna (ncrna, have some regulatory functions and may be involved in replication, transcription, there are several types of ncrna. and other processes, three types of rna are essential for protein synthesis. Requires: 6 subunits (e. coli, 8 14 subunits (eukaryotes, template (dna, activated precursors (rntps, divalent cation cofactor (mg2+ or mn2+)