My god, epigenetics is a woo-magnet.
Its not epigenetics fault, its just science.
But the word ‘epigenetics’ gets put on this (‘chambery thing’ heh.).
And… well, just Google it. Find your own favorite bit of self-help/explain all/magic epigenetic crap.
STOP WHORING UP EPIGENETICS. IT IS NOT MAGIC. ITS JUST THAT ‘BORING SCIENCE CRAP’ YOU HATED IN HIGH SCHOOL.
Its science and its cool because its science.
DEAL WITH IT.
KAP1 controls endogenous retroviruses in embryonic stem cells—
Almost half of the mammalian genome is derived from virus-like entities called retroelements, many of them the result of the incorporation of endogenous retroviruses. Didier Trono and colleagues use a combination of genetic, functional and biochemical analyses to demonstrate that KRAB-associated protein 1 (KAP1)-mediated epigenetic regulation is involved in the early embryonic silencing of intracisternal A particles (IAPs), a still active and highly polymorphic subset of endogenous retroviruses. This work establishes a role for the KAP1 co-repressor in the control of endogenous retroelements during early embryonic development.
This paper is awesome. They did so much work, and only 13 authors. Theres no way I could cover it all in a blog post– but I can give you all the jist of it.
ERVs and ERV-like-thingies, IAPs, are trouble for developing babbies. If these chunks of pirate DNA are hopping and plopping around a genome, they might cause cancer in grown adults (exogenous retroviruses do cause cancer in adults), but they would immediately kill a developing babby.
Well, apparently, one of the ways genomes have evolved to keep some kinds of pirate DNA silent during the crucial process of development is epigenetics. Not ‘BIRD SONGS ARE EPIGENETICS! DIIIIRP!‘, but real ‘science’ epigenetics– You have a family of proteins in your genome, KRABs. KRABs are sequence specific, and nestle up next to DNA with their particular sequence. We have a ton of KRABs in our genome (at least 250-ish), and theyve been under strong evolutionary stress over the course of our evolution. For some of them, we know what that stress was: they recognize ERV and IAP sequences. But KRABs themselves have no ‘function’. They just recognize sequence.
KAP-1 (aka TRIM28) sees the KRABs. KAP-1 is the opposite of KRABs– they have a function, but not really any specificity. It dunno where to go. BUT, if it finds a KRAB, it knows just what to do!
KAP-1 trundles over to a KRAB with a chromatin remodeling complex (histone methyltransferases, heterochromatin proteins, histone deacetylases), thus silences the surrounding DNA, thus keeps ERVs/IAPs silent.
They figured out some of the protein players in epigenetic control of ERVs.
Remember this post the next time you read some feather-brained article on epigenetics. Does what theyre writing, what theyre saying, look like this?