Prieto Ignacio, Pezzi Nieves, Buesa Jose M, Kremer Leonor, Barthelemy Isabel, Carreiro Candelas, Roncal Fernando, Martinez Alicia, Gomez Lucio, Fernandez Raul, Martinez-A Carlos, Barbero Jose L
Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, UAM Campus de Cantoblanco, Madrid E-28049, Spain.
EMBO Rep. 2002 Jun;3(6):543-50. doi: 10.1093/embo-reports/kvf108. Epub 2002 May 24.
STAG/SA proteins are specific cohesin complex subunits that maintain sister chromatid cohesion in mitosis and meiosis. Two members of this family, STAG1/SA1 and STAG2/SA2,double dagger are classified as mitotic cohesins, as they are found in human somatic cells and in Xenopus laevis as components of the cohesin(SA1) and cohesin(SA2) complexes, in which the shared subunits are Rad21/SCC1, SMC1 and SMC3 proteins. A recently reported third family member, STAG3, is germinal cell-specific and is a subunit of the meiotic cohesin complex. To date, the meiosis-specific cohesin complex has been considered to be responsible for sister chromatid cohesion during meiosis. We studied replacement of the mitotic by the meiotic cohesin complex during mouse germinal cell maturation, and we show that mammalian STAG2 and Rad21 are also involved in several meiosis stages. Immunofluorescence results suggest that a cohesin complex containing Rad21 and STAG2 cooperates with a STAG3-specific complex to maintain sister chromatid cohesion during the diplotene stage of meiosis.
STAG/SA蛋白是特定的黏连蛋白复合体亚基，在有丝分裂和减数分裂中维持姐妹染色单体的黏连。该家族的两个成员，即STAG1/SA1和STAG2/SA2，被归类为有丝分裂黏连蛋白，因为它们在人类体细胞和非洲爪蟾中作为黏连蛋白（SA1）和黏连蛋白（SA2）复合体的组成成分被发现，其中共享的亚基是Rad21/SCC1、SMC1和SMC3蛋白。最近报道的第三个家族成员STAG3是生殖细胞特异性的，是减数分裂黏连蛋白复合体的一个亚基。迄今为止，减数分裂特异性黏连蛋白复合体被认为在减数分裂期间负责姐妹染色单体的黏连。我们研究了小鼠生殖细胞成熟过程中有丝分裂黏连蛋白复合体被减数分裂黏连蛋白复合体取代的情况，并且我们发现哺乳动物的STAG2和Rad21也参与了几个减数分裂阶段。免疫荧光结果表明，含有Rad21和STAG2的黏连蛋白复合体与一个STAG3特异性复合体协同作用，以在减数分裂双线期维持姐妹染色单体的黏连。
