Seminar paper 3: pseudogenes

Question 1

What was the purpose of this paper?

Answer 1

Determine if the PTEN pseudogene is actually useless or if it has a biological function in the tumour suppressor function of PTEN

Question 2

How did the authors differentiate between PTEN mRNA and PTENP1 mRNA?

Answer 2

Used primers that bound to the less conserved regions in the 3’ UTR

Question 3

How similar are the PTEN and PTENP1 transcripts?

Answer 3

Only 18 mismatches between them. The start codon is knocked out so it doesn’t get translated, and the 3’ UTR is 1 kb shorter. There’s a region of high, moderate, and low homology in what remains of the 3’ UTR

Question 4

Why did the authors think that miRNAs that target PTEN might also target PTENP1?

Answer 4

Seed sequences in the highly conserved region of the 3’ UTR

Question 5

What was the model that the authors were proposing about the interactions between PTEN, PTENP1, and miRNAs?

Answer 5

miRNAs would target PTENP1 instead of PTEN, so that would increase the abundance of PTEN. Then it could be translated and do its tumour suppression function while PTENP1 acts as a decoy and draws the miRNAs away

Question 6

What happened when the authors overexpressed the miRNAs?

Answer 6

Expression of both PTEN and PTENP1 decreased

Question 7

What happened when the authors overexpressed the 3’ UTR of PTENP1?

Answer 7

Expression of PTEN increased and cell proliferation decreased

Question 8

What happened when the authors overexpressed PTEN?

Answer 8

Cell proliferation decreased

Question 9

What happened when the authors knocked down the miRNAs?

Answer 9

Expression of both PTEN and PTENP1 increased

Question 10

What happened when the authors knocked down PTENP1?

Answer 10

PTEN expressed decreased and cell proliferation increased

Question 11

What happened when the authors knocked down PTEN?

Answer 11

PTENP1 expression decreased and cell proliferation increased

Question 12

What is the technical name for the decoy mechanism?

Answer 12

Derepression