| First Author | Meglicki M | Year | 2012 |
| Journal | Cell Cycle | Volume | 11 |
| Issue | 11 | Pages | 2189-205 |
| PubMed ID | 22622086 | Mgi Jnum | J:315732 |
| Mgi Id | MGI:6829879 | Doi | 10.4161/cc.20705 |
| Citation | Meglicki M, et al. (2012) Appearance and heterochromatin localization of HP1alpha in early mouse embryos depends on cytoplasmic clock and H3S10 phosphorylation. Cell Cycle 11(11):2189-205 |
| abstractText | Pericentric constitutive heterochromatin surrounds centromeric regions and is important for centromere function and chromatid cohesion. HP1 (heterochromatin protein 1), a homolog of yeast Swi6, has been shown to be indispensible for proper heterochromatin structure and function. In mammalian somatic cells, two HP1 isoforms, HP1alpha and HP1beta, are constitutively present in pericentric heterochromatin until late G 2, when they dissociate from heterochromatin. Subsequently, they re-associate with heterochromatin at late anaphase. In one-cell mouse embryos, pericentric heterochromatin has a unique configuration and features. It does not form heterochromatin clusters observed in somatic cells and known as chromocenters. Instead, in both pronuclei, it surrounds nucleolar precursor bodies (NBPs), forming ring-like structures. These regions contain HP1beta but lack HP1alpha in both pronuclei. In subsequent interphases, HP1beta is constitutively found in heterochromatin until the blastocyst stage. It is not known when HP1alpha appears and what is its function in early mouse embryos. Here, we show that HP1alpha appears for the first time at late S phase of two-cell stage, at the time when pericentric heterochromatin is replicated. Its appearance is regulated at the level of translation. In two-cell embryos, the amount of HP1alpha that can bind to these regions is regulated by phosphorylation of serine 10 of histone H3 (H3S10Ph). Elimination of HP1alpha by siRNA interfered with centromere relocation from heterochromatin surrounding NPBs to pro-chromocenters at the two-cell stage but did not affect preimplantation develoment to the blastocyst stage. |
