Cti1/C1D interacts with condensin SMC hinge and supports the DNA repair function of condensin.
Condensin is a conserved five-subunit complex containing two SMC (structural maintenance of chromosomes) and three non-SMC subunits and plays a major role in mitotic chromosome condensation. Condensin also acts in interphase and is required for DNA repair and replication checkpoint control. We attempted to study the function of the condensin in greater detail by means of the isolation of interacting proteins with the two-hybrid system. Using the hinge domain of Cut3/SMC4 as bait, we found one Cut three-interacting (Cti) 14-kDa nuclear protein, Cti1. GST pull-down assay and immunoprecipitation supported physical interaction between Cti1 and condensin. Cti1 is similar to human C1D, which associates tightly with genomic DNA and functions to activate DNA protein kinase. SpC1D is essential for viability. The null mutant could germinate but arrest after replication, indicating that it is required for interphase growth. Importantly, an elevated dosage of spC1D suppressed the temperature, UV irradiation, and hydroxyurea sensitivity of the mutant of Cnd2, a non-SMC subunit of condensin. Upon exposure to hydroxyurea, spC1D accumulated on the nuclear chromatin, and the fraction of spC1D that was chromatin-bound increased. Cti1 is the first example of the protein that interacts with the hinge domain of SMC. Cti1 may have a supporting role for the DNA repair function of condensin.
Chen
Ee Sin
ES
Department of Gene Mechanisms, Graduate School of Biostudies, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
Sutani
Takashi
T
Yanagida
Mitsuhiro
M
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism*; D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002466:Cell Nucleolus / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002843:Chromatin / Q000187:drug effects / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D006918:Hydroxyurea / Q000494:pharmacology; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C454839:Cnd2 protein, S pombe; C487507:Cti1 protein, S pombe; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins; C108312:condensin complexes; C090207:cut3 protein, S pombe; D000251:Adenosine Triphosphatases; D006918:Hydroxyurea