Euchromatin could be what gives stem cells their stemness.
A screen for factors that both reduce embryonic stem (ES) cells’ ability to expand and diminish their expression of stem cell marker Oct4 yielded just one that hadn’t been seen before: the chromatin-remodeling enzyme Chd1.
Chd1 recognizes di-or tri-methylated histone 3 at lysine 4 (H3K4me2/3) – a hallmark of activated chromatin. And the Chd1 gene itself is bound by all sorts of transcription factors — like Oct4 and Nanog — associated with pluripotency and self-renewal.
An international team led by UCSF’s Miguel Ramalho-Santos used RNAi to knockdown Chd1. Most of the usual ES cell suspects were expressed in the usual amounts. But genes involved in neurogenesis were also kicked up, and the ES cells lost the ability to form primitive ectoderm. They accumulated lots of heterochromatin, and histone H1 turnover was compromised as well.
See why openness counts when it comes to stemness, at Nature, July 2009