RNA Processing

Question 1

5’ Capping Steps

Answer 1

1) Remove phosphate from 5’
2) Add GTP as guanyline monophosphate
3) Methylate guanine
4) Methylate ribose moities

Recognized by initiation factors when time to translate RNA

Question 2

PolyA Tail Steps

Answer 2

1) RNAP recognizes AAUAAA cleavage signal
2) Adds polyA tail to 3’ end downstream of where endonuclease cut – no compliment in DNA template

Stabilizes RNA by wrapping around protein to protect from RNAse

Question 3

Spliceosomes

Answer 3

SnRNP complex (SnRNA and Sm proteins) that assembles on mRNA – cuts 5’, pulls exons together, then cuts 3’ to form phosphodiester bond.

Forms intermediate lariat structure with intron.