Fig. 7
From: Chromatin organization changes during the establishment and maintenance of the postmitotic state
Heterochromatin clustering during terminal differentiation is a consequence of cell cycle exit. CycD, Cdk4 and E2F were co-expressed in the posterior wing to bypass robust cell cycle exit without preventing terminal differentiation. The anterior–posterior boundary is indicated by a white line. (A–D) Pupal wings at 42–44 h were dissected stained for actin and PH3 to label mitoses. Mitoses are evident in cells generating wings hairs, a hallmark of wing terminal differentiation (E) and the wings generate intact adult wing cuticle. C, D show optical cross sections (x/z) of wings reveal PH3 and actin-rich hairs in the same section. F–K CycD, Cdk4 and E2F expression in the posterior wing prevents G0 entry and disrupts proper localization of heterochromatin-associated histone modifications and HP1. J The distribution of staining intensity in 474–1191 nuclei, binned into three ranges is shown. The reduced foci number (I) and intensity (K) indicate compromised clustering of H3K27me3 containing chromatin when entry into G0 is prevented. P values were determined by an unpaired t test; ****< 0.0001. Scale bars = 10 μm in A, 5 μm in B and 2.5 μm in D