lecture 15

Question 1

forward genetics

Answer 1

finding the genetic basis for a phenotype

Question 2

reverse genetics

Answer 2

understanding the phenotype associated with a gene

Question 3

examples of forward genetics

Answer 3

drosophila segmentation genetic screen

Question 4

reverse genetics examples

Answer 4

gene silencing, targeted mutagenesis, RNAi, CRISPR

Question 5

morpholinos

Answer 5

synthetic oligonucleotides that are usually 25 bps. they target mRNAs to block their transcription

Question 6

do morpholinos destroy mRNAs?

Answer 6

no

Question 7

RNAi

Answer 7

ancient immunity pathway against transposable elements and/or viral elements

Question 8

what else is RNAi used for?

Answer 8

gene-regulation

Question 9

what does RNAi utilize?

Answer 9

dsRNA but its rare in the cell, except those that are made by viruses

Question 10

components of RNAi

Answer 10

RNA and RISC

Question 11

what is involved in RNA?

Answer 11

siRNA and miRNA

Question 12

what is involved in RISC

Answer 12

a complex of proteins and the main component is Argonaute

Question 13

siRNAs

Answer 13

double stranded and binds to the complementary portion of the target mRNA. Targets mRNA for degradation

Question 14

Dicer

Answer 14

protein that cleaves the original dsRNA into siRNAs, and the siRNAs are loaded into the RISC

Question 15

what does the guide strand of in siRNAs?

Answer 15

it acts as a template to “recognize” the target mRNA, and once its found Argonaute cleaves the mRNA

Question 16

what encodes miRNAs?

Answer 16

endogenous genes

Question 17

what regulates gene expression?

Answer 17

dimmer switch

Question 18

do miRNAs require processing before activation?

Answer 18

yes

Question 19

where does the pre-mRNA enter?

Answer 19

the cytoplasm

Question 20

how does miRNA turn into RNAi?

Answer 20

1. its cut into 22 bps long by dicer
2. the now mature miRNA is integrated into the RISc with Argonaute
3. Argonaute can now use one strand as a guide