Manzanero S, Arana P, Puertas M J, Houben A
Departamento de Genética, Facultad de Biología, Universidad Complutense, Madrid, Spain.
Chromosoma. 2000;109(5):308-17. doi: 10.1007/s004120000087.
Plant (Secale cereale, Triticum aestivum) and animal (Eyprepocnemis plorans) meiocytes were analyzed by indirect immunostaining with an antibody recognizing histone H3 phosphorylated at serine 10, to study the relationship between H3 phosphorylation and chromosome condensation at meiosis. To investigate whether the dynamics of histone H3 phosphorylation differs between chromosomes with a different mode of segregation, we included in this study mitotic cells and also meiotic cells of individuals forming bivalents plus three different types of univalents (A chromosomes, B chromosomes and X chromosome). During the first meiotic division, the H3 phosphorylation of the entire chromosomes initiates at the transition from leptotene to zygotene in rye and wheat, whereas in E. plorans it does so at diplotene. In all species analyzed H3 phosphorylation terminates toward interkinesis. The immunosignals at first meiotic division are identical in bivalents and univalents of A and B chromosomes, irrespective of their equational or reductional segregation at anaphase I. The grasshopper X chromosome, which always segregates reductionally, also shows the same pattern. Remarkable differences were found at second meiotic division between plant and animal material. In E. plorans H3 phosphorylation occurred all along the chromosomes, whereas in plants only the pericentromeric regions showed strong immunosignals from prophase II until telophase II. In addition, no immunolabeling was detectable on single chromatids resulting from equational segregation of plant A or B chromosome univalents during the preceding anaphase I. Simultaneous immunostaining with anti-tubulin and anti-phosphorylated H3 antibodies demonstrated that the kinetochores of all chromosomes interact with microtubules, even in the absence of detectable phosphorylated H3 immunosignals. The different pattern of H3 phosphorylation in plant and animal meiocytes suggests that this evolutionarily conserved post-translational chromatin modification might be involved in different roles in both types of organisms. The possibility that in plants H3 phosphorylation is related to sister chromatid cohesion is discussed.
通过用识别丝氨酸10位点磷酸化组蛋白H3的抗体进行间接免疫染色，对植物（黑麦、普通小麦）和动物（鼓翅皱膝蝗）的减数分裂细胞进行分析，以研究减数分裂过程中H3磷酸化与染色体凝聚之间的关系。为了研究具有不同分离模式的染色体之间组蛋白H3磷酸化的动态变化是否存在差异，我们在本研究中纳入了有丝分裂细胞以及形成二价体加三种不同类型单价体（A染色体、B染色体和X染色体）个体的减数分裂细胞。在第一次减数分裂期间，黑麦和小麦中整个染色体的H3磷酸化在细线期向偶线期过渡时开始，而在鼓翅皱膝蝗中则在双线期开始。在所有分析的物种中，H3磷酸化在减数分裂间期结束。第一次减数分裂时的免疫信号在二价体以及A和B染色体的单价体中是相同的，无论它们在后期I是进行均等分离还是减数分离。总是进行减数分离的蝗虫X染色体也显示出相同的模式。在第二次减数分裂时，在植物和动物材料之间发现了显著差异。在鼓翅皱膝蝗中，H3磷酸化沿着整个染色体发生，而在植物中，只有着丝粒周围区域从前期II到末期II都显示出强烈的免疫信号。此外，在前期I进行均等分离的植物A或B染色体单价体产生的单条染色单体上未检测到免疫标记。用抗微管蛋白和抗磷酸化H3抗体同时进行免疫染色表明，即使在没有可检测到的磷酸化H3免疫信号的情况下，所有染色体的动粒都与微管相互作用。植物和动物减数分裂细胞中H3磷酸化的不同模式表明，这种进化上保守的翻译后染色质修饰在这两种生物中可能发挥不同的作用。文中讨论了植物中H3磷酸化与姐妹染色单体黏连相关的可能性。
