microRNA regulation

Question 1

What are the four mechanisms of miRNA regulation

Answer 1

1. The basic approach
2. Broad effects approach
3. The functional approach
4. The pathway-based approach

Question 2

Define the basic approach

Answer 2

Single microRNA - mRNA interactions

Question 3

Define the broad effects approach

Answer 3

One microRNA to many mRNAs

Question 4

Define the functional approach

Answer 4

o A single microRNA inhibits two mRNAs, preventing a combined effect

Question 5

Define the pathway based approach

Answer 5

o A transcription factor activates microRNAs, leading a to a cascade of mRNA inhibitions, preventing the effect

Question 6

Define Context-dependent transcriptional activation

Answer 6

An miRNA inhibits a transcription factor, preventing expression of a gene

Question 7

Define Transcriptional Default Repression

Answer 7

When the inhibition signal is weak, the miRNA will attack the products of transcription, inhibiting expression

Question 8

Define Role of miRNA in damage response

Answer 8

in presence of DNA damage, miR-125 is inhibited, allowing p53 to initiate apoptosis

Question 9

List two ways that micrRNAs affect signalling gradients

Answer 9

• miRNA modifies tissue responsiveness overtime

- Target inhibitors of signal cascades

Question 10

How can miRNAs be used as bistable fate choices?

Answer 10

State A occurs where an miRNA is expressed, causing the miRNA target, a transcription factor, to be inhibited

Question 11

Give two examples of miRNAs as oncogenes with definitions

Answer 11

• miR-21: found to be upregulated in all forms of cancer

- miR-155: overexpression of this miRNA alone can cause leukemia or lymphoma in transgenic mice