Abstract
In meiotic prophase, the sister chromatids of each chromosome develop a common axial element (AE) that is integrated into the synaptonemal complex (SC). We analyzed the incorporation of sister chromatid cohesion proteins (cohesins) and other AE components into AEs. Meiotic cohesin REC8 appeared shortly before premeiotic S phase in the nucleus and formed AE-like structures (REC8-AEs) from premeiotic S phase on. Subsequently, meiotic cohesin SMC1beta, cohesin SMC3, and AE proteins SCP2 and SCP3 formed dots along REC8-AEs, which extended and fused until they lined REC8-AEs along their length. In metaphase I, SMC1beta, SMC3, SCP2, and SCP3 disappeared from the chromosome arms and accumulated around the centromeres, where they stayed until anaphase II. In striking contrast, REC8 persisted along the chromosome arms until anaphase I and near the centromeres until anaphase II. We propose that REC8 provides a basis for AE formation and that the first steps in AE assembly do not require SMC1beta, SMC3, SCP2, and SCP3. Furthermore, SMC1beta, SMC3, SCP2, and SCP3 cannot provide arm cohesion during metaphase I. We propose that REC8 then provides cohesion. RAD51 and/or DMC1 coimmunoprecipitates with REC8, suggesting that REC8 may also provide a basis for assembly of recombination complexes.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acid Anhydride Hydrolases
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Anaphase / genetics
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Animals
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cells, Cultured
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Chondroitin Sulfate Proteoglycans*
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism*
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Chromosomes / genetics
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Chromosomes / metabolism
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Cohesins
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DNA Repair Enzymes*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Fluorescent Antibody Technique
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Fungal Proteins
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Immunohistochemistry
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Male
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Meiosis / genetics*
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Models, Biological
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Phosphoproteins / genetics
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Phosphoproteins / metabolism*
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Rad51 Recombinase
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Rats
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S Phase / genetics
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Spermatocytes / cytology
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Spermatocytes / metabolism*
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Synaptonemal Complex / metabolism*
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Synaptonemal Complex / ultrastructure
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Testis / cytology
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Testis / metabolism
Substances
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Cell Cycle Proteins
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Chondroitin Sulfate Proteoglycans
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Chromosomal Proteins, Non-Histone
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Cspg6 protein, mouse
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DNA-Binding Proteins
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Fungal Proteins
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Nuclear Proteins
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Phosphoproteins
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Rec8 protein, mouse
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SMC3 protein, human
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SMC3 protein, rat
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SYCP3 protein, human
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Smc1l2 protein, mouse
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Sycp2 protein, rat
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Sycp3 protein, mouse
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Sycp3 protein, rat
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Rad51 Recombinase
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Rad51 protein, rat
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Acid Anhydride Hydrolases
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RAD50 protein, human
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DNA Repair Enzymes