Dynamic and Stable Cohesins Regulate Synaptonemal Complex Assembly and Chromosome Segregation.
Assembly of the synaptonemal complex (SC) in Drosophila depends on two independent pathways defined by the chromosome axis proteins C(2)M and ORD. Because C(2)M encodes a Kleisin-like protein and ORD is required for sister-chromatid cohesion, we tested the hypothesis that these two SC assembly pathways depend on two cohesin complexes. Through single- and double-mutant analysis to study the mitotic cohesion proteins Stromalin (SA) and Nipped-B (SCC2) in meiosis, we provide evidence that there are at least two meiosis-specific cohesin complexes. One complex depends on C(2)M, SA, and Nipped-B. Despite the presence of mitotic cohesins SA and Nipped-B, this pathway has only a minor role in meiotic sister-centromere cohesion and is primarily required for homolog interactions. C(2)M is continuously incorporated into pachytene chromosomes even though SC assembly is complete. In contrast, the second complex, which depends on meiosis-specific proteins SOLO, SUNN, and ORD is required for sister-chromatid cohesion, localizes to the centromeres and is not incorporated during prophase. Our results show that the two cohesin complexes have unique functions and are regulated differently. Multiple cohesin complexes may provide the diversity of activities required by the meiotic cell. For example, a dynamic complex may allow the chromosomes to regulate meiotic recombination, and a stable complex may be required for sister-chromatid cohesion.
Waksman Institute and Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8020, USA.
Mercedes R
MR
Gyuricza
Waksman Institute and Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8020, USA.
Kathryn B
KB
Manheimer
Waksman Institute and Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8020, USA.
Vandana
V
Apte
Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840, USA.
Badri
B
Krishnan
Waksman Institute and Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8020, USA.
Eric F
EF
Joyce
Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840, USA.
Bruce D
BD
McKee
Waksman Institute and Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8020, USA. Electronic address: mckim@rci.rutgers.edu.
Kim S
KS
McKim
D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism; D023902:Chromosome Pairing; D020090:Chromosome Segregation; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D013573:Synaptonemal Complex / Q000235:genetics*; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D019476:Insect Proteins; D000097722:Cohesins
chromosome segregation; cohesin; cohesion; meiosis; synaptonemal complex