Trigger 8: Non-coding RNA

Question 1

a non-coding RNA (ncRNA)

Answer 1

is an RNA molecule that is not translated into a protein

Question 2

how much of transcriptional output is ncRNA

Answer 2

97-98%

Question 3

ncRNA is probs not

Answer 3

part of the central dogma, due to it being non-coding

Question 4

types of ncRNA

Answer 4

rRNA (ribosomal)
tRNA (transfer)
RNAi (interference)

Question 5

two types of RNAi

Answer 5

miRNA and siRNA

Question 6

miRNA

Answer 6

small RNA involved in regulation of expression

Question 7

iRNA

Answer 7

small interfering RNA which activates molecules in RNA interference

Question 8

ncRNA function to

Answer 8

regulate gene expression at the transcriptional ad post transcriptional level

Question 9

two main groups of ncRNA involved in epigenetic processes

Answer 9

short ncRNA

long ncRNA

Question 10

short ncRNA

Answer 10

<200 nts

Question 11

long ncRNA

Answer 11

> 200 nts

Question 12

both groups of ncRNA

Answer 12

are shown to play a role in heterochromatin formation, histone modification, DNA methylation, targeting and gen silencing

Question 13

microRNAs are

Answer 13

small ncRNAs (22nts long)

Question 14

miRNA do what to gene expression

Answer 14

repress gene expression

Question 15

miRNA are involved in

Answer 15

development, differentiation, proliferation and apoptosis

Question 16

how to miRNA exert their effect

Answer 16

by base pairing to complementary mRNA sequences

Question 17

miRNA induce a silencing complex called

Answer 17

RISC

Question 18

RISC

Answer 18

RNA-idncued silencing complex

Question 19

mRNA complexed with RISC

Answer 19

cannot be expressed

Question 20

miRNA expression is

Answer 20

tissue specific and highly regulated according to cells developmental lineage and stage

Question 21

process of how miRNA exerts effect

Answer 21

1) pro-miRNA are transcribed
2) drosha processing produces pre-miRNA
3) pre-miRNA is exported out of the nucleus by Exportin-5
4) formation of RISC complex (mature miRNA)
5) binds to mRNA- causes translational repression

Question 22

what does miRNA complex with

Answer 22

complementary to the 3/UTR of the target mRNA- inhibiting translation