DNA-binding domain of RCC1 protein is not essential for coupling mitosis with DNA replication.
The RCC1 protein that is required for coupling mitosis with the S phase has a DNA-binding domain in the N-terminal region outside the repeat. We found that RCC1 protein without any DNA-binding activity complemented the tsBN2 mutation with the same efficiency as that of intact RCC1 protein. In ts+ transformants of tsBN2 cells transfected with the RCC1 cDNA lacking the DNA-binding domain, an endogenous RCC1 disappeared at 39.5 degrees C, and the deleted RCC1 protein encoded by the transfected cDNA was found in the cytoplasm, but a significant amount of it was also found in the nuclei. This deleted RCC1 protein was eluted from the nuclei with the same concentration of NaCl and DNase I as was used for the intact RCC1 protein in BHK21 cells. Furthermore, the deleted RCC1 protein co-migrated with the nucleosome fraction on sucrose density gradient analysis. These results indicate that the RCC1 protein binds chromatin with the aid of other unknown protein(s). Thus, the DNA-binding domain of RCC1 protein is not essential for coupling between the S and M phases, but was shown instead to function as a nuclear translocation signal.
Seino
H
H
Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan.
Hisamoto
N
N
Uzawa
S
S
Sekiguchi
T
T
Nishimoto
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018797:Cell Cycle Proteins; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism; D002872:Chromosome Deletion; D004252:DNA Mutational Analysis; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000502:physiology*; D020662:Guanine Nucleotide Exchange Factors; D051379:Mice; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000502:physiology; D021382:Protein Sorting Signals; D014162:Transfection
D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D009687:Nuclear Proteins; D021382:Protein Sorting Signals; C499302:Rcc1 protein, mouse