Crossing over is coupled to late meiotic prophase bivalent differentiation through asymmetric disassembly of the SC.
Crossing over is coupled to late meiotic prophase bivalent differentiation through asymmetric disassembly of the SC.
复制标题
通过SC的不对称拆卸，交叉耦合到减数分裂的晚期二价分化。
DOI：
10.1083/jcb.200410144
复制
发表时间：
2005-02-28
影响因子：
7.8
通讯作者：
Colaiacovo, Monica P
中科院分区：
文献类型：
--
作者：
Nabeshima, Kentaro;Villeneuve, Anne M;Colaiacovo, Monica P
同源染色体对（二价染色体）在减数分裂前期进行重组，将促进交叉重组的结构转化为促进双极纺锤体附着和局部内聚丧失的结构。我们对秀丽隐杆线虫粗线素退出后减数分裂染色体结构的重塑进行了成像。染色体缩短伴随着染色体轴的盘绕和突触复合体（SC）中心区域蛋白SYP-1和SYP-2的高度不对称离开，它们在每个去突触二价的大部分长度上减少，而集中在单个出现交叉的远端轴段。这种和其他染色体不对称的表现在精通突触的交叉缺陷突变体中消失了，这种突变体通常在盘绕的二倍体轴的整个长度上保留syp -1,2。此外，γ辐照处理恢复了spo-11突变体中的交叉，也恢复了SYP-1定位的不对称性。我们提出交叉或交叉前体作为对称破坏事件，通过触发SC的不对称分解来促进二价亚区分化。
Homologous chromosome pairs (bivalents) undergo restructuring during meiotic prophase to convert a configuration that promotes crossover recombination into one that promotes bipolar spindle attachment and localized cohesion loss. We have imaged remodeling of meiotic chromosome structures after pachytene exit in Caenorhabditis elegans. Chromosome shortening during diplonema is accompanied by coiling of chromosome axes and highly asymmetric departure of synaptonemal complex (SC) central region proteins SYP-1 and SYP-2, which diminish over most of the length of each desynapsing bivalent while becoming concentrated on axis segments distal to the single emerging chiasma. This and other manifestations of asymmetry along chromosomes are lost in synapsis-proficient crossover-defective mutants, which often retain SYP-1,2 along the full lengths of coiled diplotene axes. Moreover, a γ-irradiation treatment that restores crossovers in the spo-11 mutant also restores asymmetry of SYP-1 localization. We propose that crossovers or crossover precursors serve as symmetry-breaking events that promote differentiation of subregions of the bivalent by triggering asymmetric disassembly of the SC.