Characterization and dynamic analysis of Arabidopsis condensin subunits, AtCAP-H and AtCAP-H2.
Condensin complexes are thought to play essential roles in mitotic chromosome assembly and segregation in eukaryotes. To date, two condensin complexes (condensin I and II) have been identified. Both complexes contain two structural maintenance of chromosome (SMC) subunits and three non-SMC subunits. In plants, little is known about the localization and function of all the condensin subunits. Here, we report the analyses on the localization of a non-SMC subunit of Arabidopsis condensin I and II, AtCAP-H, and AtCAP-H2, respectively. Our study indicated that localization of AtCAP-H and AtCAP-H2 is dynamically changed through the mitotic cell cycle using GFP-tagged AtCAP-H and AtCAP-H2 in tobacco cultured cells. They are localized at mitotic chromosomes from prometaphase to telophase. However, their localization in interphase is quite different. AtCAP-H was mainly found in the cytoplasm whereas AtCAP-H2 was mainly found in a nucleolus. It is revealed using GFP-tagged deletion mutant s of AtCAP-H that the kleisin-gamma middle domain (GM domain) is a unique domain only in AtCAP-H, responsible for chromosomal localization. We propose that the GM domain of CAP-H is essential for its chromosomal localization at mitosis and thus proper function of CAP-H. Differences in localization of AtCAP-H and AtCAP-H2 at interphase also suggest their functional differentiation.
Fujimoto
Satoru
S
Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka, 565-0871, Japan.
Yonemura
Masataka
M
Matsunaga
Sachihiro
S
Nakagawa
Tsuyoshi
T
Uchiyama
Susumu
S
Fukui
Kiichi
K
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D032461:Chromosomes, Plant / Q000378:metabolism; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008938:Mitosis; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; C506884:CAP-H protein, Arabidopsis; C506885:CAP-H2 protein, Arabidopsis; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D021122:Protein Subunits; C108312:condensin complexes; D000251:Adenosine Triphosphatases