Figure 3

Single light-optical sections showing the distribution of HP1β (red) and centromeres (green) in early (a, 4 hpa) and late (b-c, 10 hpa) 1-cell SCNT embryos, with or without TSA treatment. At 4 hpa (a) centromeres are decondensed and mainly localized at NPB peripheries, occasionally associated with HP1β accumulations (insert). At 10 hpa (b-c) centromeres are more condensed and located at NPB (arrowheads) or nuclear peripheries (arrows). However, two types of embryos can be distinguished: the first one (b and c, top row) harboring more than 3 centromeres at the nuclear periphery, not associated to NPBs (as in 51% of the untreated embryos) whereas the second one (b and c, bottom row) exhibit 3 or less centromeres not associated with the NPBs (as in 76% of the embryos after transient treatment with TSA). Scale bars, 5 μm.