Imprinting 2 better Flashcards
(16 cards)
Which pronucleus is demethylated first?
The male
What has happened to the male pronucleus before any cell division has occured?
It has rapidly lost its methylation
What is responsible for the rapid demethylation of the male pronucleus?
TET enzymes
What happens to imprinted genes post fertilisation?
The imprints are maintained
Which type of epigenetic marks can be passed onto the next generation?
Imprinted marks
When are imprinted genes not resistant to demethylation?
Prior to fertilisation
What is the state of a gene on the opposite chromosome to the same gene that has been imprinted?
It is inactive
Why do imprinted genes share regulatory elements?
They occur in clusters
What is different between the imprinting control regions on different genes?
They are differentially methylated (i.e. one allele is methylated while the other isnt)
How many genes can an imprinting control region?
Multiple
What could happen if the imprinting control region at a certain locus is deleted?
All the imprinting at that locus may be lost
What is different between the two genes in a differentially methylated region?
The methylation and thus the chromatin conformation (methylated allele will have a more closed, compacted less accessible chromatin conformation than the unmethylated one)
Examples of genomic imprinting disorders?
Silver Russell and Beckwith Wiedemann syndromes, neonatal and maternal hypomethylation syndrome
What is x inactivation?
After fertilisation, when you have two x chromosomes one is inactivated
Difference between genomic imprinting and x inactivation?
Genomic imprinting is non-random whereas x inactivation is random
