Discussion this week:

biochemical pathways splicing RNA processing

transcript modifications in eukaryotes

co-transcriptional (aka post-transcriptional)

pre-mRNA processing

TFIIH

(YSPTSPS)52

C-terminal domain

initiation

splicing

capping

polyadenylation

•  protects against degradation •  ribosome binding

•  generates diversity

•  transcription termination •  transport to cytoplasm •  mRNA stability •  translation efficiency

“transcription unit”

transcription unit complexity: splicing

splicing: producing the “translatable” protein coding region(s)

intron intron intron exon exon exon exon

“Problem 5.15”

Consensus sequences necessary for correct splicing

Nomenclature: junctions named relative to INTRONS

splice junction

5´ donor 3´ acceptor

spliceosome assembly

snRNAs + proteins = snRNPs (snurps)

EM image of 2 genes being transcribed

rRNA genes