Chromatin loading of Smc5/6 is induced by DNA replication but not by DNA double-strand breaks.
Smc6, a member of the structural maintenance of chromosomes (SMC) family of proteins, forms a complex with related Smc5. Genetic analyses of yeast have demonstrated the involvement of Smc6 in DNA repair and checkpoint responses. In this study, we investigated the role of the Smc5/6 complex in higher eukaryotes by analyzing its behavior in Xenopus laevis egg extracts. Smc5/6 was loaded onto chromatin during DNA replication in a manner dependent on the initiation of DNA synthesis, and it dissociated from chromatin during mitosis. Moreover, the induction of DNA double-strand breaks following replication did not significantly affect the amount of chromatin-associated Smc6. These findings suggest that the Smc5/6 complex is regulated during the cell cycle, presumably in anticipation of DNA damage that may arise during replication.
Tsuyama
Takashi
T
Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan.
Inou
Katsutoshi
K
Seki
Masayuki
M
Seki
Takahiko
T
Kumata
Yuji
Y
Kobayashi
Takayuki
T
Kimura
Keiji
K
Hanaoka
Fumio
F
Enomoto
Takemi
T
Tada
Shusuke
S
D000818:Animals; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004261:DNA Replication; D016195:G2 Phase; D008938:Mitosis; D016196:S Phase; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C516333:Smc5 protein, Xenopus; D029867:Xenopus Proteins; C516334:smc6.1 protein, Xenopus