Analysis on the nuclear apoptosis indispensable for sexual reproduction in a ciliate, Paramecium.

纤毛虫草履虫有性繁殖所必需的核细胞凋亡分析。

基本信息

批准号：
15603001
负责人：
MIKAMI Kazuyuki
金额：
$ 2.3万
依托单位：
Research Institute on Environmental Education, Miyagi University of Education
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Programmed nuclear death occurs in unicellular eukaryotes such as ciliates. In the present work, nuclear apoptosis was investigated from the point of view of nuclear interaction among maternal macronuclei, newly developed macronuclei, maternal micronuclei and newly developed micronuclei. In Paramecium caudatum, programmed nuclear death occurs three times during conjugation (Mikami, 2000).The first of the three selective nuclear degeneration events occurring is the degeneration of meiotic products of the micronucleus. When cells enter the conjugative phase the micronucleus undergoes meiosis and produces four haploid micronuclei. One of these moves into an area called the paroral cone and survives while the other three soon degenerate.The remaining nucleus divides once and produces gametic nuclei (gametogenesis). The gametic micronuclei are exchanged reciprocally between mating cells and form diploid zygotic nuclei. A zygotic nucleus (synkaryon) divides three times to give rise to eight … More nuclei. Four of these differentiate into macronuclear anlagen and the other four became presumptive micronuclei. The four macronuclear anlagen are distributed without nuclear division to daughter cells in two cell divisions after conjugation. For the four presumptive micronuclei, it is known that one remains and the other three degenerate. This is the second nuclear degeneration. The results obtained lead us to a conclusion that most of the micronuclei remained at least by the first post-conjugation fission and that only one of them was selected to divide at the first fission (Taka et al, 2005).The third selective degeneration of nuclei occurs with the parental macronucleus and the macronuclear anlagen (Kimura et al., 2004). After conjugation, the parental macronucleus fragments into pieces that retain the functions of the macronucleus. After several fissions, however, the macronuclear fragments degenerate selectively. If newly developed macronucleus was removed just before the degeneration of macronuclear fragments, the gene expression of the fragments could be reprogrammed to be juvenile (Kimura and Mikami, 2003). Less

编程的核死亡发生在单细胞真核生物（例如纤毛）中。在目前的工作中，从母体大核中的核相互作用的角度研究了核凋亡，新开发的大核，母体微核和新开发的微核。在尾tar象中，编程的核死亡发生了三次（Mikami，2000）。发生的三个选择性核变性事件中的第一个是微核的减数分裂产物的变性。当细胞进入共轭阶段时，微核会经历减数分裂并产生四个单倍体微核。其中一个移动到一个名为charoral锥的区域，并幸存下来，而其他三个很快就退化了。其余的核一次分裂并产生配子核（配子发生）。配子型微核在交配细胞之间相互交换，并形成二倍体合子核。合子核us（Synkaryon）划分三次，产生八个……更多的核。其中四个分化为大核Anlagen，另外四个变成了可覆盖的微核。四个大核Anlagen在共轭后的两个细胞分裂中没有核分裂分布。对于四个可预处理的微核，众所周知，另一个遗体，另外三个退化。这是第二个核变性。获得的结果导致我们得出一个结论，即至少在第一个偶联后裂变时，大多数微核一直保持不变，并且只有其中一个被选为第一次裂变（Taka等，2005）。核的第三个选择性变性发生在亲本大核和大核Anlagen（Kimura等，2004）。结合后，父母大核片段成碎片，保留了大核的功能。然而，经过几次裂变，大核片段有选择地退化。如果在大核片段变性之前将新开发的大核被去除，则可以将片段的基因表达重编程为少年（Kimura和Mikami，2003）。较少的