Condensins, chromosome condensation protein complexes containing XCAP-C, XCAP-E and a Xenopus homolog of the Drosophila Barren protein.
We report here purification and characterization of chromosome condensation protein complexes (termed condensins) containing XCAP-C and XCAP-E, two Xenopus members of the SMC family. Sucrose density gradient centrifugation reveals two major forms of condensins. The 8S form is a heterodimer of XCAP-C and XCAP-E, whereas the 13S form contains three additional subunits. One of them is identified as a homolog of the Drosophila Barren protein whose mutation shows a defect in chromosome segregation. Chromosomal targeting of condensins is mitosis-specific and is independent of topoisomerase IIalpha. 13S condensin is required for condensation, as demonstrated by immunodepletion and rescue experiments. Our results suggest that the condensin complexes represent the most abundant structural components of mitotic chromosomes and play a central role in driving chromosome condensation.
Hirano
T
T
Cold Spring Harbor Laboratory, New York 11724, USA.
Kobayashi
R
R
Hirano
M
M
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000818:Animals; D000951:Antigens, Neoplasm; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D002499:Centrifugation, Density Gradient; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D002875:Chromosomes / Q000737:chemistry; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D019281:Dimerization; D004330:Drosophila; D029721:Drosophila Proteins; D005260:Female; D007527:Isoenzymes / Q000378:metabolism; D046911:Macromolecular Substances; D008938:Mitosis; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D010063:Ovum / Q000737:chemistry; D010766:Phosphorylation; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014981:Xenopus; D029867:Xenopus Proteins
D000951:Antigens, Neoplasm; C103227:Barr protein, Drosophila; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D007527:Isoenzymes; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; C109974:NCAPH protein, human; D009687:Nuclear Proteins; C490381:SMC2 protein, human; C090452:SMC4 protein, Xenopus; C090453:XCAP-E protein, Xenopus; D029867:Xenopus Proteins; C108312:condensin complexes; D000251:Adenosine Triphosphatases; D004250:DNA Topoisomerases, Type II