Analysis of Meiosis using Hybrid-male-sterile Animals.

减数分裂是功能生殖细胞形成的重要过程之一，其主要过程是同源染色体的断裂、同源染色体之间的遗传重组（交叉）和交叉形成以及染色体的分离（分离）。这些事件中的任何一个失败都会导致缺乏生殖细胞和不育。尽管关于减数分裂的细胞学和细胞遗传学研究已经积累了很多，但利用酵母对减数分裂事件进行的分子分析才刚刚开始，但在高等生物中仍然很少。然而，了解和控制减数分裂事件可以为育种，生育和不育问题以及人类福祉做出不可估量的贡献。我们对雄性不育动物牦牛（F1 of Bos taurus X Bos grunniens）、鹿Cerus elaphus X Cerus nippon F1 （deer）、猴m.s fasicularis X m.a assamesis F1 （monkey）的睾丸和卵巢细胞进行了细胞学和分子生物学分析。目前我们已经用牦牛完成了我们的研究。杂交雄不育鹿尚未到手，杂交不育猴已死亡，昆明研究所的下一步生产尚存疑问。以下是我们今天的实验结果：雄性不育是由减数分裂降解引起的，主要发生在叶绿体期，部分发生在分裂期和中期。然而，在卵母细胞中也观察到类似的减数分裂降解，表明卵母细胞数量减少。利用大肠杆菌制备的抗RecA蛋白和Lim15（百合减数分裂前期特异性基因）蛋白的抗体，即使在不育的睾丸中，也能与大多数减数分裂细胞正结合，而在包括睾丸和卵巢在内的体细胞中几乎没有观察到抗体的结合。从不育和可育（正常牛）动物减数分裂前期细胞中分离的DNA聚合酶β和α的活性从细胞蛋白的角度看基本相同。从不育和可育睾丸减数分裂前细胞分离的cDNA克隆在限制性内切图谱和数量上相似，表明不育雄性减数分裂前细胞中发生了正常的转录。所有这些都可以给我们一个线索，得出以下结论，但这是初步的，需要进一步仔细的研究。所谓的男性不育是由于减数分裂破裂导致精子减少而引起的。这也发生在女性身上。由于一个卵细胞就能获得雌性的生育能力，所以尽管卵母细胞的数量减少，雌性还是有生育能力的。到目前为止所检查的分子事件表明，在可育性和不育性之间没有可检测到的差异，直到前期或中期。这些杂交种的减数分裂降解可能是由于突变小鼠的细胞凋亡，但这需要更多的分析。少

Meiosis is one of the important process for formation of the functionally reproductive cells and the major events are the piring of homologous chromosomes, genetic recombination (crossing-over) and chiasma-formation between them and segregation of chromosomes (disjunction).The failure of any one of these events leads to lack of reproductive cells and sterility. Despite the accumulation of many cytological and cytogenetical studies on meiosis, molecular analyzes of meiotic events are just underway using yeasts, but still scarece in higher organisms. Nevertheless, understanding and control of meiotic events could make uncountable contribution for breeding, fertility and sterility problems and human welfare. We have tried to analyze testicular and ovarian cells from the male-sterile animals, Yak (F1 of Bos taurus X Bos grunniens), Cerus elaphus X Cerus nippon F1 (deer), M.fascicularis X M.assamesis F1 (monkey), cytologically and molecular biologically using our antibodies to recombination … More al enzymes and various probes prepared from the meiotically active genes. Currently we have completed our studies using yaks. The hybrid-male-sterile deers are not yet in our hand, while hybrid-sterile-monkey died and the next production is questionable in Kunming Institute. The followings are our experimental results today :1.The male-sterility is caused by meiotic degradation mostly during pchytene and some at diakinesis and metaphase I.However, the similar meiotic degradation has been observed in oocytes, suggesting the reduction in number of the oocytes. The antibody prepared against RecA protein and Lim15 (lily meiotic prophase I-specific gene) protein using E.coli have positively bound to most of meiotic cells even from sterile testes, while little binding has been observed in somatic cells including the testicular and the ovarian ones.2.Acivities of DNA polymerase beta and alpha isolated from meioic prophase cells of sterile and fertile (normal ox) animal are essentially the same, based on the cellular protein.3.Isolated cDNA clones from sterile and fertile testicular meiotic prophase cells are similar in restriction maps and quantities obtained, suggesting that the normal transcription is occurring in meiotic prophase cells from the sterile males.All of these can gives us a clue to conclude the following but it is preliminary and further carefull studies should be carried out.1.So-called male-sterility is caused by the meiotic break down lead to reduction of sperm. This occurs also in female. Since female fertility is obtainable with one egg cell, the female is fertile despite the reduction in the number of oocytes.2.The molecular events so far examined indicated that there is no detectable difference between the fertiles and the steriles until either prophase or metaphase. The meiotic degradation in these hybrids may be due to apoptosis as speculated in mutant mouse, but this requirs more analysis. Less