DYNAMIC CHANGES IN RAD51 DISTRIBUTION ON CHROMATIN DURING MEIOSIS IN MALE AND FEMALE VERTEBRATES
DYNAMIC CHANGES IN RAD51 DISTRIBUTION ON CHROMATIN DURING MEIOSIS IN MALE AND FEMALE VERTEBRATES
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DOI：
10.1007/s004120050088
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发表时间：
1995-10-01
期刊：
影响因子：
1.6
通讯作者：
WARD, DC
中科院分区：
文献类型：
--
作者：
ASHLEY, T;PLUG, AW;WARD, DC
用抗人Rad 51蛋白的抗体检测小鼠精母细胞、卵母细胞和鸡卵母细胞减数分裂各阶段中RadS 1在减数分裂染色质上的分布。我们观察到在减数分裂过程中Rad 51分布的动态变化：（1）在细线期早期的细胞核中，有多个明显随机分布的焦点，到细线期晚期，这些焦点被组织成焦点的轨迹。(2)这些病灶持续到zygonema，但大多数病灶现在定位于Rad 51阳性轴，对应于联会复合体的侧元素。同源轴上的突触灶与同源轴上的突触灶融合。Rad 51病灶作为同系物之间的接触点的分布和参与表明它们可能是早期重组结节的组成部分。(3)随着粗线的进展，病灶的数量急剧下降;时间发生（小鼠）和轴（鸡）上病灶的物理和数值分布表明，它们可能是晚期重组结节的一个组成部分。(4)在粗线体早期，在X（小鼠精母细胞）或Z（鸡卵母细胞）染色体的单轴上有许多RadS 1病灶，既不配对，也不重组。(5)在小鼠精母细胞的粗线体晚期，而不是卵母细胞中，RadS 1信号在所有二价体的两端优先增强。精母细胞中的二价体开始在双丝体处去突触，而卵母细胞中的二价体则不然，它们通常在这些Rad 51阳性末端处结合在一起。这些观察平行观察，重组率异常高的染色体末端附近的男性，但不是女性真兽目哺乳动物。(6)从终变期到中期I，Rad 51蛋白被检测为低强度的荧光双峰，与CREST特异性抗原（动粒）定位，这表明Rad 51参与，至少作为所涉及的材料的结构组成部分，在姐妹动粒凝聚力。最后，Rad 51分布在减数分裂过程中的变化似乎不是物种特异性的，但内在的减数分裂过程。
Antibodies against human Rad51 protein were used to examine the distribution of RadS1 on meiotic chromatin in mouse spermatocytes and oocytes as well as chicken oocytes during sequential stages of meiosis. We observed the following dynamic changes in distribution of Rad51 during meiosis: (1) in early leptotene nuclei there are multiple, apparently randomly distributed, foci that by late leptonema become organized into tracks of foci. (2) These foci persist into zygonema, but most foci are now localized on Rad51-positive axes that correspond to lateral elements of the synaptonemal complex. As homologs synapse foci from homologous axes fuse. The distribution and involvement of Rad51 foci as contact points between homologs suggest that they may be components to early recombination nodules. (3) As pachynema progresses the number of foci drops dramatically; the temporal occurrence (mice) and physical and numerical distribution of foci on axes (chickens) suggest that they may be a component of late recombination nodules. (4) In early pachynema there are numerous RadS1 foci on the single axis of the X (mouse spermatocytes) or the Z (chicken oocytes) chromosomes that neither pair, nor recombine. (5) In late pachynema in mouse spermatocytes, but not oocytes, the RadS1 signal is preferentially enhanced at both ends of all the bivalents. As bivalents in spermatocytes, but not oocytes, begin to desynapse at diplonema they are often held together at these Rad51-positive termini. These observations parallel observations that recombination rates are exceptionally high near chromosome ends in male but not female eutherian mammals. (6) From diakinesis through metaphase I, Rad51 protein is detected as low-intensity fluorescent doublets that localize with CREST-specific antigens (kinetochores), suggesting that Rad51 participates, at least as a structural component of the materials involved, in sister kinetochore cohesiveness. Finally, the changes in Rad51 distribution during meiosis do not appear to be species specific, but intrinsic to the meiotic process.