Key points: summarized from chapter 14 RNA processing
Outline: we will focus on mRNA processing Overview of the Central Dogma Link DNA to RNA transcription to proteintranslation What is a codon? Gene organization Introns and exons What really is a gene? Steps of pre-mRNA processing Eukaryotes versus prokaryotes
Gene Organization: Is DNA and RNA co-linear?
3 steps of mRNA processing occurs in the nucleus of eukaryotes 5’ CAP Poly-A tail Splicing
The 5’Cap
The Poly-A Tail
Cleavage by endonuclease
Basic steps of poly-Adenylation
Splicing Spliceosome Requires RNA + proteins Self splicing Only RNA! Function as enzymes Self splicing Only RNA! Function as enzymes!
Spliceosome Meet the spliceosome
Splicesome: 3 components are required Note some important aspects of the 5’ and 3’ ends 5’ phosphodiester of G 2’ OH of A lariat
Where does splicing occurs?
Self-Splicing mRNA’s
Common characteristic of self-splicing mRNA’s
Comments on Alternative processing methods First: What are the methods of mRNA processing discussed so far? 5’ CAP 3’ Poly A Tail Intron Splicing
Alternative processing methods Alternative splicing Multiple 3’cleavage sites RNA editing
And alternative splicing example Thryoid BRAIN
Silencing or interfering RNAs siRNA miRNA
Onto translation chapter 15