Fission yeast hrp1, a chromodomain ATPase, is required for proper chromosome segregation and its overexpression interferes with chromatin condensation.
Hrp1 of Schizosaccharomyces pombe is a member of the CHD protein family, characterized by a chromodomain, a Myb-like telobox-related DNA-binding domain and a SNF2-related helicase/ATPase domain. CHD proteins are thought to be required for modification of the chromatin structure in transcription, but the exact roles of CHD proteins are not known. Here we examine the sub-cellular localization and biochemical activity of Hrp1 and the phenotypes of hrp1 Delta and Hrp1-overexpressing strains. Fluorescence microscopy revealed that Hrp1 protein is targeted to the nucleus. We found that Hrp1 exhibited DNA-dependent ATPase activity, stimulated by both single- and double-stranded DNA. Overexpression of Hrp1 caused slow cell growth accompanied by defective chromosome condensation in anaphase resulting in a 'cut' (celluntimelytorn) phenotype and chromosome loss. The hrp1 Delta mutation also caused abnormal anaphase and mini-chromosome loss phenotypes. Electron micrographs demonstrated that aberrantly shaped nucleoli appeared in Hrp1-overexpressing cells. Therefore, these results suggest that Hrp1 may play a role in mitotic chromosome segregation and maintenance of chromatin structure by utilizing the energy from ATP hydrolysis.
Yoo
E J
EJ
Department of Molecular Biology and Research Center for Cell Differentiation, Seoul National University, Seoul, Republic of Korea.
Jin
Y H
YH
Jang
Y K
YK
Bjerling
P
P
Tabish
M
M
Hong
S H
SH
Ekwall
K
K
Park
S D
SD
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000705:Anaphase; D002466:Cell Nucleolus / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D002467:Cell Nucleus / Q000737:chemistry; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation; D015825:Chromosomes, Fungal / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000502:physiology; D019084:Fluorescent Antibody Technique, Indirect; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D006868:Hydrolysis; D008938:Mitosis; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D039221:mRNA Cleavage and Polyadenylation Factors
D002843:Chromatin; C512636:HRP1 protein, S cerevisiae; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D029701:Saccharomyces cerevisiae Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases