Genomic imprinting

Question 1

How does imprinting take place?

Answer 1

In the embryo, genes subjected to imprinting are marked by DNA methylation according to their origin. Imprinted genes are protected from the wave of demethylation taking place after fertilisation, so the imprinted gene remains silent

Question 2

What can genomic imprinting be regulated by?

Answer 2

lncRNA

Question 3

Environmental exposures that regulate imprinting

Answer 3

1. Age of oocyte
2. Obesity
3. Metabolic status
4. In vitro fertilisation

Question 4

Describe the Kcnq1

Answer 4

A gene only transcribed when inherited from the mother. The regulation is through DNA methylation which takes place inside the transcription unit of this protein-coding gene. This regulates the expression of lncRNA

Question 5

Paternal allele in Kcnq1

Answer 5

the paternal allele has no methylation so the lncRNA can be expressed and the gene is repressed

Question 6

When can CTCF protein recognise a sequence?

Answer 6

Only if it is not methylated