Fig. 1.

ATRX is required for recruitment of the histone chaperone DAXX to pericentric heterochromatin in the paternal genome. (A,B) ATRX (red) is transmitted to the early zygote through the maternal germ line (arrows) where it becomes enriched at pericentric heterochromatin (PCH) upon pronuclear formation. ATRX becomes detectable in the paternal pronucleus (arrowheads) at 6 h post-fertilization (hpf). (C,D) Coincident with nucleolar formation, ATRX localizes to PCH in both maternal and paternal pronuclei at 12 hpf. DAXX (green) is recruited to PCH in both pronuclei but is enriched in the paternal pronucleus. (E,F) ATRX-deficient zygotes fail to recruit DAXX to PCH in both maternal and paternal pronuclei (inset). Scale bars: 10 µm.