genetics post-transcriptional and translational regulation

alternative splicing

pre-mRNAs of man euky genes may be spliced in alt ways to generate different mRNA isoforms that include or emit different exons

what controls which isoform gets produced?

spliceosomes

proteome

number of proteins that an organism can make

Drosophila genome contains about 140000 what

protein coding genes

the Dscam gene alone encodes 2.5x that many what

proteins

most eukaryotic mRNAs are degraded by what

deadenylation dependent mRNA decay

3 methods of deadenylation dependent mRNA decay

deadenylase enzyme shortens polyA tail to <30nt, decapping enzyme removes 5’ cap, or exoribonuclease xRNI can degrade mRNA from 5’ to 3’

RNA interference (RNAi)

employs siRNAs or miRNAs to silence specific mRNA transcripts

siRNA or mRNA leads RISC to a

complementary strand; if match is exact, mRNA is cleaved; if not, mRNA is inhibited from translation

long coding RNAs binding function

bind to DNA and bring in chromatin modification complex

lncRNA decoy function

instead of larger mRNA binding to miRNA and RISC, it binds along non-coding RNA

lncRNA scaffold function

help different protein complexes come together