TH2B is a major histone variant that replaces about 80–85% of somatic H2B in mammalian spermatocytes and spermatids. The post-translational modifications (PTMs) on TH2B have been well characterised in spermatocytes and spermatids. However, the biological function(s) of these PTMs on TH2B have not been deciphered in great detail. In our attempt to decipher the unique function(s) of histone variant TH2B, we detected the modification in the N-terminal tail, Serine 11 phosphorylation on TH2B (TH2BS11ph) in spermatocytes. The current study is aimed at understanding the function of the TH2BS11ph modification in the context of processes that occur during meiotic prophase I. Immunofluorescence studies with the highly specific antibodies revealed that TH2BS11ph histone mark is enriched in the unsynapsed axes of the sex body and is associated with XY body-associated proteins like Scp3, γH2AX, pATM, ATR, etc. Genome-wide occupancy studies as determined by ChIP sequencing experiments in P20 C57BL6 mouse testicular cells revealed that TH2BS11ph is enriched in X and Y chromosomes confirming the immunofluorescence staining pattern in the pachytene spermatocytes. Apart from the localisation of this modification in the XY body, TH2BS11ph is majorly associated with H3K4me3-containing genomic regions like gene promoters, etc. These data were also found to corroborate with the ChIP sequencing data of TH2BS11ph histone mark carried out in P12 C57BL6 mouse testicular cells, wherein we found the predominant localisation of this modification at H3K4me3-containing genomic regions. Mass spectrometry analysis of proteins that associate with TH2BS11ph-containing mononucleosomes revealed key proteins linked with the functions of XY body, pericentric heterochromatin and transcription. TH2BS11ph modification is densely localised in the unsynapsed axes of the XY body of the pachytene spermatocyte. By ChIP sequencing studies in mouse P12 and P20 testicular cells, we demonstrate that TH2BS11ph is predominantly associated with H3K4me3 positive genomic regions like gene promoters, etc. We propose that TH2BS11ph modification could act alone or in concert with other histone modifications to recruit the appropriate transcription or XY body recombination protein machinery at specific genomic loci.

中文翻译：

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TH2BS11ph组蛋白标记富集在XY体的未突触轴上，并主要与哺乳动物精母细胞中含H3K4me3的基因组区域相关。

TH2B是一种主要的组蛋白变体，可替代哺乳动物精细胞和精细胞中约80–85％的体细胞H2B。TH2B的翻译后修饰（PTM）已在精母细胞和精子细胞中得到很好的表征。但是，尚未对这些PTM在TH2B上的生物学功能进行详细的解释。在尝试破译组蛋白变体TH2B的独特功能时，我们检测到了N末端尾部的修饰，即精母细胞TH2B（TH2BS11ph）上的丝氨酸11磷酸化。当前的研究旨在了解TH2BS11ph修饰在减数分裂前期I发生的过程中的功能。用高度特异性抗体进行的免疫荧光研究表明，TH2BS11ph组蛋白标记富集在性器官的未突触轴上，并与XY身体相关蛋白（例如Scp3，γH2AX，pATM，ATR等）相关。在P20 C57BL6小鼠睾丸细胞中进行的ChIP测序实验表明，TH2BS11ph富含X和Y染色体，证实了粗线精子细胞中的免疫荧光染色模式。除了这种修饰在XY体内的定位外，TH2BS11ph还与包含H3K4me3的基因组区域（如基因启动子等）相关。这些数据也与在P12 C57BL6小鼠中进行的TH2BS11ph组蛋白标记的ChIP测序数据相符。睾丸细胞 其中我们发现了这种修饰的主要定位在包含H3K4me3的基因组区域。质谱分析与含TH2BS11ph的单核小体相关的蛋白质，揭示了与XY体功能，周围异染色质和转录功能相关的关键蛋白质。TH2BS11ph修饰密集地位于粗线精母细胞XY体的未突触轴上。通过在小鼠P12和P20睾丸细胞中进行ChIP测序研究，我们证明TH2BS11ph主要与H3K4me3阳性基因组区域（如基因启动子等）相关。我们建议TH2BS11ph修饰可以单独起作用或与其他组蛋白修饰协同起作用以募集适当的转录或在特定基因组位点的XY身体重组蛋白机制。