Bromodomain containing (BRD) proteins play an essential role in many cellular processes. The aim of this study was to estimate activity of bromodomains during alga Chara vulgaris spermatids differentiation. The effect of a bromodomain inhibitor, JQ1 (100 µM), on the distribution of individual stages of spermatids and their ultrastructure was studied. The material was Feulgen stained and analysed in an electron microscope. JQ1 caused shortening of the early stages of spermiogenesis and a reverse reaction at the later stages. Additionally, in the same antheridium, spermatids at distant developmental stages were present. On the ultrastructural level, chromatin fibril system disorders and significantly distended endoplasmic reticulum (ER) cisternae already at the early stages were observed. Many autolytic vacuoles were also visible. The ultrastructural disturbances intensified after prolonged treatment with JQ1. The obtained data show that JQ1 treatment led to changes in the spermatid number and disturbances in chromatin condensation and to cytoplasm reduction. The current studies show some similarities between C. vulgaris and mammals spermiogenesis. Taken together, these results suggest that JQ1 interferes with the spermatid differentiation on many interdependent levels and seems to induce ER stress, which leads to spermatid degeneration. Studies on the role of bromodomains in algae spermiogenesis have not been conducted so far.

中文翻译：

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阻断Bromodomains功能有助于扰乱海藻寻常型精子细胞的分化。

含溴结构域（BRD）的蛋白质在许多细胞过程中起着至关重要的作用。这项研究的目的是评估藻类Chara vulgaris期间bromodomains的活性精子分化。研究了溴结构域抑制剂JQ1（100 µM）对精子各个阶段分布及其超微结构的影响。该材料经过Feulgen染色，并在电子显微镜下进行了分析。JQ1导致精子发生早期阶段的缩短，并在后期阶段引起逆反应。此外，在同一个花药中，存在着处于较远发育阶段的精子。在超微结构水平上，已经在早期观察到染色质原纤维系统疾病和明显扩张的内质网（ER）池。还可见许多自溶性液泡。JQ1长期治疗后，超微结构障碍加剧。获得的数据表明，JQ1处理导致精子数量的变化，染色质浓缩的紊乱和细胞质的减少。当前的研究表明寻常梭状芽胞杆菌和哺乳动物的精子发生。综上所述，这些结果表明，JQ1在许多相互依赖的水平上干扰精子分化，并且似乎诱导ER应激，从而导致精子变性。迄今为止，尚未对溴结构域在藻类精子发生中的作用进行研究。