Exoribonucleases (lect 12)

Question 1

Components of the TRAMP complex (in nucleus)

Answer 1

-Mtr4 (RNA helicase, and has arch that interacts with proteins)
-Trf4 (polyA polymerase)
-Rrp6 (prot connecting complex to exosome)

Question 2

Components of the Ski complex (in cytoplasm)

Answer 2

-Ski2 (RNA helicase)
-Ski7 (prot connecting complex to exosome, bound where Rrp6 bound)

Question 3

What is the substrate of 5’-3’ exonucleases?

Answer 3

RNAs with a 5’ monophosphate

Question 4

How is a 5’ monophosphate generated?

Answer 4

by endonucleases and decapping enzymes
eg. Rai1 (converts tri to mono phosphate and decaps) and Dxo1 (homologue to Rai1)

Question 5

Components of NNS complex

Answer 5

RNA-binding proteins Nrd1 and Nab3
RNA helicase Sen1

Question 6

What is the role of terminal nucleotide transferases when helping the exosome?

Answer 6

add poly(A) or poly(U) which acts as binding platform for RNase to bind to