de Almeida Bruno Rafael Ribeiro, Noronha Renata Coelho Rodrigues, da Costa Marlyson Jeremias Rodrigues, Nagamachi Cleusa Yoshiko, Pieczarka Julio Cesar
Laboratório de Citogenética, Centro de Estudos Avançados em Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Avenida Augusto Corrêa, s/n, 66075-900, Guamá, Belém, Pará, Brazil.
Laboratório de Citogenética, Centro de Estudos Avançados em Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará, Avenida Augusto Corrêa, s/n, 66075-900, Guamá, Belém, Pará, Brazil
Biol Open. 2019 May 9;8(5):bio040352. doi: 10.1242/bio.040352.
Achiasmatic male meiosis in scorpions is characterized by a high frequency of gaps, asynaptic regions and multivalent associations. Here, we performed an immunocytogenetic analysis to investigate recombination, and synapsis and chromatin-remodeling events during meiosis of the scorpion Our results demonstrate that the synaptonemal complex (SC) begins its organization in the zygotene stage and persists until metaphase I. The advancement of the synaptic process is related to the epigenetic modification histone H3 lysine 27 trimethylation (H3K27m3). The distribution and dynamics patterns of variant γH2AX and recombinase Rad51 during achiasmatic meiosis suggests formation and repair of DNA double-strand breaks (DSBs) during early stages of prophase I. The epigenetic modifications, histone H3 lysine 4 trimethylation (H3K4m3) and histone H3 lysine 9 acetylation (H3K9ac), showed a dispersed distribution along the bivalents, suggesting that transcriptional activity is maintained constitutively during prophase I. However, H3K9ac modifications are absent in constitutive heterochromatin carrying the 45S rDNA in pachytene and post-pachytene stages. Collectively, our data demonstrate that exhibits adaptations to the achiasmatic mode, and suggest that epigenetic modifications may act in the regulation of these mechanisms to favor the normal continuation of meiosis in this scorpion.
蝎子的无交叉雄性减数分裂的特征是出现间隙、非联会区域和多价联会的频率很高。在此，我们进行了一项免疫细胞遗传学分析，以研究蝎子减数分裂过程中的重组、联会和染色质重塑事件。我们的结果表明，联会复合体（SC）在偶线期开始形成，并持续到中期I。联会过程的进展与表观遗传修饰组蛋白H3赖氨酸27三甲基化（H3K27m3）有关。在无交叉减数分裂过程中，变异体γH2AX和重组酶Rad51的分布和动态模式表明，在前期I的早期阶段会形成和修复DNA双链断裂（DSB）。表观遗传修饰组蛋白H3赖氨酸4三甲基化（H3K4m3）和组蛋白H3赖氨酸9乙酰化（H3K9ac）沿二价体呈分散分布，这表明在前期I期间转录活性持续存在。然而，在粗线期和粗线期后阶段，携带45S rDNA的组成型异染色质中不存在H3K9ac修饰。总体而言，我们的数据表明，蝎子表现出对无交叉模式的适应性，并表明表观遗传修饰可能在这些机制的调节中发挥作用，以利于这种蝎子减数分裂的正常延续。
