Chromosomal addresses of the cohesin component Mcd1p
Chromosomal addresses of the cohesin component Mcd1p
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DOI：
10.1083/jcb.151.5.1047
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发表时间：
2000-11-27
影响因子：
7.8
通讯作者：
Koshland, D
中科院分区：
文献类型：
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作者：
Laloraya, S;Guacci, V;Koshland, D
我们通过染色质免疫沉淀结合基于高分辨率PCR的染色体行走，在体内鉴定了粘附素亚单位Mcd1p的染色体地址。在几条染色体的单拷贝序列中绘制新的Mcd1p结合位点(粘附素相关区域[CARS])，确定了它们的间距(Ngkb)、它们与基因间隔区的隔离以及它们与富含AT的序列的关联，这是CARS的一般基因组特性。我们发现，粘附素不排除在端粒近端区域，并且在有丝分裂着丝粒上粘附素的丰富反映了从头开始的加载。汽车的平均大小为0.8-1.0kb。它们位于转录沉默区域的边界，这表明它们在定义沉默染色质结构域方面发挥了直接作用。最后，我们识别了串联的CARS(RDNA)和散布的重复DNA(TY2和亚端粒重复)。每个9kb的rDNA重复序列在5S基因附近都有一辆CAR。因此，单复制区和rDNA重复序列中CARS的周期性是保守的。重复DNA中CARS的存在和间距对基因组稳定性和染色体包装/凝聚具有重要意义。
We identified the chromosomal addresses of a cohesin subunit, Mcd1p, in vivo by chromatin immunoprecipitation coupled with high resolution PCR-based chromosomal walking. The mapping of new Mcd1p-binding sites (cohesin-associated regions [CARs]) in single-copy sequences of several chromosomes establish their spacing (Ng kb), their sequestration to intergenic regions, and their association with AT-rich sequences as general genomic properties of CARs. We show that cohesins are not excluded from telomere proximal regions, and the enrichment of cohesins at the centromere at mitosis reflects de novo loading. The average size of a CAR is 0.8-1.0 kb. They lie at the boundaries of transcriptionally silenced regions, suggesting they play a direct role in defining the silent chromatin domain. Finally, we identify CARs in tandem (rDNA) and interspersed repetitive DNA (Ty2 and subtelomeric repeats). Each 9-kb rDNA repeat has a single CAR proximal to the 5S gene. Thus, the periodicity of CARs in single-copy regions and the rDNA repeats is conserved. The presence and spacing of CARs in repetitive DNA has important implications for genomic stability and chromosome packaging/condensation.