Characterization and dynamic analysis of Arabidopsis condensin subunits, AtCAP-H and AtCAP-H2

Abstract

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.

Overexpression of theRADICAL-INDUCED CELL DEATH1(RCD1) Gene of Arabidopsis Causes Weakrcd1Phenotype with Compromised Oxidative-Stress Responses

“…A 3.9-kb RCD1 genomic sequence, which covered entire RCD1 coding region, was amplified by PCR using a pair of primers, 5 0 -CACCACCCAATAAGATTTCGACGTT-3 0 and 5 0 -AGGAGAACCACAAAGGCAGGTAG-3 0 , and cloned in a Gateway entry vector pENTR/D-TOPO (Invitrogen, Carlsbad, CA, USA). The genomic fragment was then inserted into pGWB8 binary vector downstream of the 35S promoter of cauliflower mosaic virus 10) by the Gateway system (Invitrogen) and introduced into Agrobacterium tumefaciens strain pGV2260. The nucleotide sequence was confirmed by sequencing.…”

Condensin II Alleviates DNA Damage and Is Essential for Tolerance of Boron Overload Stress in Arabidopsis

“…In this study, we characterized two of these mutants, heb1-1 and heb2-1, and found that HEB1 and HEB2 encode chromosomal-associated protein (CAP)-G2 and CAP-H2, respectively, two subunits of the chromosomal protein complex known as condensin II (Fujimoto et al, 2005).…”

Transcriptional homogenization of rDNA repeats in the episome-based nucleolus induces genome-wide changes in the chromosomal distribution of condensin

“…It facilitates timely sister chromatid compartmentalization and faithful chromosome segregation during cell division. Eukaryotic condensin complex subunits are conserved from yeast to human (Fujimoto et al, 2005;Hirano, 2005). In budding yeast Saccharomyces cerevisiae, the condensin complex is composed of five polypeptides, including the SMC heterodimer (Smc2p and Smc4p) and three non-SMC subunits (Brn1p, Ycs4p and Ycs5p/Ycg1p) (Freeman et al, 2000).…”