imprinted genes inactivation

[McFly]

Hey guys, epigenetic problem:

Let's have a gene that is paternally imprinted, ie. allele inherited from father is silent in all individuals in given generation. Now, i cannot figure out if such gene is inactive immediately after fertilization, or whether the silencing occurs during early stages of development, let say during few hours after fertilization. In other words: are the epigenetic marks on (to-be)silenced allele directly interfering with transcription or, are they just marks for heterochromatinization/silencing after fertilization?

[JackBean]

well, it seems, that it is marked during development of gametes
http://en.wikipedia.org/wiki/Genomic_Im ... mechanisms

[McFly]

That's for sure. But the question is, what "marked" means - are these marks direct cause of transcriptional inactivity of the gene or are they serving as a platform for silencing machinery in the embryo?

[JackBean]

I believe they are inactivated

[McFly]

what?

[JackBean]

they are inactivated during the production of gametes and they keep that status during embryogenesis