Mammalian STAG3 is a cohesin specific to sister chromatid arms in meiosis I.
Cohesins, which have been characterized in budding yeast and Xenopus, are multisubunit protein complexes involved in sister chromatid cohesion. Regulation of the interactions among different cohesin subunits and the assembly/disassembly of the cohesin complex to chromatin are key steps in chromosome segregation. We previously characterized the mammalian STAG3 protein as a component of the synaptonemal complex that is specifically expressed in germinal cells, although its function in meiosis remains unknown. Here we show that STAG3 has a role in sister chromatid arm cohesion during mammalian meiosis I. Immunofluorescence results in prophase I cells suggest that STAG3 is a component of the axial/lateral element of the synaptonemal complex. In metaphase I, STAG3 is located at the interchromatid domain and is absent from the chiasma region. In late anaphase I and the later stages of meiosis, STAG3 is not detected. STAG3 interacts with the structural maintenance chromosome proteins SMC1 and SMC3, which have been reported to be subunits of the mitotic cohesin complex. We propose that STAG3 is a sister chromatid arm cohesin that is specific to mammalian meiosis I.
Prieto
I
I
Department of Immunology and Oncology, Centro Nacional de Biotecnología, UAM Campus de Cantoblanco, Madrid E-28049, Spain.
Suja
J A
JA
Pezzi
N
N
Kremer
L
L
Martínez-A
C
C
Rufas
J S
JS
Barbero
J L
JL
D000818:Animals; D018797:Cell Cycle Proteins; D002503:Centromere / Q000235:genetics / Q000378:metabolism; D002842:Chromatids / Q000235:genetics*; D002868:Chromosomal Proteins, Non-Histone; D020090:Chromosome Segregation / Q000502:physiology*; D004268:DNA-Binding Proteins; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins; D000882:Haplorhini; D008297:Male; D008322:Mammals / Q000235:genetics* / Q000378:metabolism; D008540:Meiosis / Q000235:genetics*; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D009924:Organ Culture Techniques; D012854:Sister Chromatid Exchange / Q000235:genetics*; D013090:Spermatocytes / Q000166:cytology / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000378:metabolism; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D000097722:Cohesins; C489753:SYCP1 protein, human; C490060:SYCP3 protein, human; C498637:Stag3 protein, mouse; C489754:Sycp1 protein, mouse; C490062:Sycp3 protein, mouse