Nt. The y axis shows % spermatocytes with unsynapsed trivalents and precise BRCA1 enrichment patterns.doi: 10.1371/journal.pone.0075970.gPLOS A single | www.plosone.orgMeiotic Silencing in Robertsonian TranslocationsFigure three. Localization from the heterochromatin mark, histone H3K9me3, at unsynapsed trivalents in meiotic prophase I spermatocytes from carriers of a single or 3 translocations. Z – zygotene, EP early pachytene, LP late pachytene, D diplotene spermatocytes. Arrows point to the XY bivalents. Arrowheads indicate unsynapsed trivalents. The bottom sets of panels show only SC immunostaining to facilitate the identification of unsynapsed regions along with the XY-bivalent. A-D – spermatocytes from wild kind mice; E-H – spermatocytes from carriers of one translocation; I- L – spermatocytes from carriers of 3 translocations. A, E and I ygotene spermatocytes with H3K9me3 enrichment all through the nucleus. In wild type mice, H3K9me3 is enriched in the sex physique in early pachytene (B), is lost in mid and late (C) pachytene and reappears in diplotene (D) spermatocytes. F- an unsynapsed autosomal trivalent in early pachytene spermatocytes from a single translocation carrier shows enrichment with H3K9me3 when connected with or in close proximity for the sex body.Dabigatran etexilate G an unsynapsed trivalent in a mid pachytene spermatocyte from a single translocation carrier shows distinct H3K9me3 localization at centromeres, but not the rest with the unsynapsed region. The XY-bivalent inside the very same nucleus shows H3K9me3 enrichment only in the centromere with the Xchromosome. H diplotene spermatocyte from a single translocation carrier with H3K9me3 enrichment at the sex body. J in carriers of three translocations, unsynapsed autosomal trivalents in early pachytene spermatocytes show enrichment with H3K9me3 when linked with or in close proximity for the sex body. K ynapsed trivalents within a late pachytene spermatocyte from a carrier of three translocations show H3K9me3 localization at centromeres. The XY-bivalent in the same nucleus shows H3K9me3 enrichment only at the centromere from the X-chromosome. L XY-body enrichment with H3K9me3 in diplotene spermatocytes from carriers of 3 translocations.doi: 10.1371/journal.pone.0075970.gPLOS One | www.plosone.orgMeiotic Silencing in Robertsonian TranslocationsFigure four. Exclusion of the inactive chromatin mark histone H3K27me3 from unsynapsed chromosomal regions is limited towards the XY-bivalent in single translocation carriers. Z – zygotene, EP early pachytene, LP late pachytene, D diplotene spermatocytes. Arrows point to the XY bivalents.Saquinavir Arrowheads indicate unsynapsed trivalents.PMID:23819239 A Zygotene spermatocyte is enriched for H3K27me3; B-F – the H3K27me3 histone mark is excluded from the XY-bivalent in early (B) mid (C), late (D, E) pachytene and diplotene (F) spermatocytes. On the other hand, H3K27me3 is not excluded from the unsynapsed trivalent (B, C and E). D Only 1 of 15 late pachytene spermatocytes with unsynapsed trivalent showed H3K27me3 exclusion.doi: 10.1371/journal.pone.0075970.gpachytene stage [45]. To evaluate the H3.1/2 nucleosome replacement by H3.three nucleosomes, immunostaining experiments applying an antibody against histone H3.three phosphorylated at serine 31 (H3.3S31) were performed. In contrast to the antibody made use of by other people [45], this antibody did not detect H3.3S31 in mid or late pachytene spermatocytes but showed intense and particular immunostaining at the sex physique indiakinesis, metaphase I, anaphase I and metaphase II spermat.
