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Figure 5 | Epigenetics & Chromatin

Figure 5

From: Spatial and temporal plasticity of chromatin during programmed DNA-reorganization in Stylonychia macronuclear development

Figure 5

Histone modifications of advanced macronuclear anlagen with polytene chromosomes. Nuclear types occurring at advanced developmental stages during the first round of DNA-amplification: Polytene chromosomes are formed in the macronuclear anlage (a3). During this stage excision of internal eliminated sequences, unscrambling of macronucleus destined sequences of scrambled genes and excision of transposon-like elements occur. Besides macronuclear anlagen (a3), micronuclei (m) and fragmented parental macronuclei (p) are found in the cells. In situ antibody staining (color code as described in Figure 2): (A-J) Confocal image stack projections. (K-M) Mid light optical sections (arrows point at 'heterochromatic blocks'). H3K9ac (A), H3K14ac (B), and H3S28p (J) persist with high signal intensity in advanced macronuclear anlagen (a3), but H3K9ac/K14ac (K) is obviously omitted from large chromatin domains, 'heterochromatic blocks'. H3K4me1 (C), H3K4me3 (D), and H3K36ac (F) accumulate in macronuclear anlagen at this stage, and scattered foci-like signals of H3K36me3 (E) are also detected. High levels of H3K9me3 (G), H3K27me1 (H), and H3K27me3 (I) are introduced de novo at stage a3. H3K27me3 (L) is also detected in large chromatin domains omitted from H3 acetylation. In spread polytene chromosomes H3K27me3 (M) is detected in chromosomal bands and 'heterochromatic blocks'.

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