Lecture 9

Question 1

what are the 3 RNA editing mechanisms?

Answer 1

C deamination to U
A deamination to Inosine
Base insertions - usually U

Question 2

which proteins from edited mrna are involved in cns function

Answer 2

glutamate receptors, serotonin receptors, DNA repair enzymes

Question 3

what is ADAR

Answer 3

Adenisone deaminase acting on RNA. turns adenosine into insosine

Question 4

what is inosine translated as?

Answer 4

uracil

Question 5

ribozymes

Answer 5

ribonucleic acid enzymes

Question 6

give 3 biochemical reactions that can be catalysed by ribozymes

Answer 6

RNA splicing
RNA polymerasation
RNA cleavage and ligation

Question 7

Give 5 examples of ribozymes

Answer 7

Hammerhead
Hairpin
Ribosome 
RNAse P
Spliceosome

Question 8

miRNA

Answer 8

microRNA

small noncoding RNA molecules that can regulate eukaryotic gene expression

Question 9

how are miRNAs formed

Answer 9

pri-mRNA (RNA Pol II), stem loop structure (processing by Drosha) pre-miRNA (exportin 5), cytoplasm (cleavage Dicer), mature miRNA, recruitment by RISC

Question 10

How are miRNAs developmentally/tissue specific

Answer 10

titrate levels of key regulatory proteins important in early dvelopment, cell proliferation and cell death
Dicer is deliberately in fertilised eggs which blocks the generation of all miRNAs at this developmental stage.
If Dicer is deliberately manipulated in development specific tissues, sever growth defects are seen