Eijpe M, Heyting C, Gross B, Jessberger R
Department of Biomolecular Sciences, Laboratory of Genetics, Wageningen University, NL-6703 HA, Wageningen, The Netherlands.
J Cell Sci. 2000 Feb;113 ( Pt 4):673-82. doi: 10.1242/jcs.113.4.673.
In somatic cells, the heterodimeric Structural Maintenance of Chromosomes (SMC) proteins are involved in chromosome condensation and gene dosage compensation (SMC2 and 4), and sister chromatid cohesion and DNA recombination (SMC1 and 3). We report here evidence for an involvement of mammalian SMC1 and SMC3 proteins in meiosis. Immunofluorescence analysis of testis sections showed intense chromatin association in meiotic prophase cells, weaker staining in round spermatids and absence of the SMC proteins in elongated spermatids. In spermatocyte nuclei spreads, the SMC1 and SMC3 proteins localize in a beaded structure along the axial elements of synaptonemal complexes of pachytene and diplotene chromosomes. Both SMC proteins are present in rat spermatocytes and enriched in preparations of synaptonemal complexes. Several independent experimental approaches revealed interactions of the SMC proteins with synaptonemal complex-specific proteins SCP2 and SCP3. These results suggest a model for the arrangement of SMC proteins in mammalian meiotic chromatin.
在体细胞中，异源二聚体染色体结构维持（SMC）蛋白参与染色体浓缩和基因剂量补偿（SMC2和4），以及姐妹染色单体黏连和DNA重组（SMC1和3）。我们在此报告哺乳动物SMC1和SMC3蛋白参与减数分裂的证据。睾丸切片的免疫荧光分析显示，减数分裂前期细胞中有强烈的染色质关联，圆形精子细胞中染色较弱，而伸长的精子细胞中不存在SMC蛋白。在精母细胞核铺片中，SMC1和SMC3蛋白沿着粗线期和双线期染色体联会复合体的轴向元件定位于串珠状结构中。这两种SMC蛋白都存在于大鼠精母细胞中，并在联会复合体的制备物中富集。几种独立的实验方法揭示了SMC蛋白与联会复合体特异性蛋白SCP2和SCP3之间的相互作用。这些结果提示了哺乳动物减数分裂染色质中SMC蛋白排列的模型。
