Novel meiosis-specific isoform of mammalian SMC1
Novel meiosis-specific isoform of mammalian SMC1
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DOI：
10.1128/mcb.21.20.6984-6998.2001
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发表时间：
2001-10-01
影响因子：
5.3
通讯作者：
Jessberger, R
中科院分区：
文献类型：
--
作者：
Revenkova, E;Eijpe, M;Jessberger, R
染色体结构维持(SMC)蛋白在染色体动力学中起着关键作用。在酵母中，SMC1-SMC3异源二聚体是减数分裂姐妹染色单体凝聚和DNA重组所必需的。然而，对哺乳动物SMC蛋白在减数分裂细胞中的作用知之甚少。我们已经鉴定出一种新的SMC蛋白(SMC1β)，除了一个独特的碱性DNA结合C末端基序外，它与SMC1(现在可能被称为SMC1α)高度同源，并且不存在于酵母基因组中。SMC1β在睾丸和与SMC3的免疫共沉淀物中特异表达，但不表达于多种体细胞。这为哺乳动物细胞确立了细胞类型和组织特异性SMC蛋白亚型的概念。对减数分裂不同阶段的睾丸切片和染色体铺展的分析表明，SMC1β在前期1沿着联会复合体的轴向元件定位。在粗线期晚期细胞中，SNIC1β大部分从染色体臂上解离。然而，直到中期II之前，SMC1β而不是SMC1α在着丝粒上保持着染色质相关。因此，SMC1β而不是SMC1α可能参与维持姐妹着丝粒之间的凝聚力直到后期II。
Structural maintenance of chromosomes (SMC) proteins fulfill pivotal roles in chromosome dynamics. In yeast, the SMC1-SMC3 heterodimer is required for meiotic sister chromatid cohesion and DNA recombination. Little is known, however, about mammalian SMC proteins in meiotic cells. We have identified a novel SMC protein (SMC1 beta), which-except for a unique, basic, DNA binding C-terminal motif-is highly homologous to SMC1 (which may now be called SMC1 alpha) and is not present in the yeast genome. SMC1 beta is specifically expressed in testes and coimmunoprecipitates with SMC3 from testis nuclear extracts, but not from a variety of somatic cells. This establishes for mammalian cells the concept of cell-type- and tissue-specific SMC protein isoforms. Analysis of testis sections and chromosome spreads of various stages of meiosis revealed localization of SMC1 beta along the axial elements of synaptonemal complexes in prophase 1. Most SNIC1 beta dissociates from the chromosome arms in late-pachytene-diplotene cells. However, SMC1 beta, but not SMC1 alpha, remains chromatin associated at the centromeres up to metaphase II. Thus, SMC1 beta and not SMC1 alpha is likely involved in maintaining cohesion between sister centromeres until anaphase II.