title: Centromere dynamics in the primitive red alga Cyanidioschyzon merolae.
abstract: Centromeres are universally conserved functional units in eukaryotic linear chromosomes, but little is known about the structure and dynamics of the centromere in lower photosynthetic eukaryotes. Here we report the identification of a centromere marker protein CENH3 and visualization of centromere dynamics in the ultra-small primitive red alga Cyanidioschyzon merolae. Immunoblotting and immunofluorescence microscopy showed that CENH3 increased rapidly during S phase, followed by a drastic reconstitution into two discrete foci adjacent to the spindle poles at metaphase, suggesting the cell-cycle-regulated expression of CENH3. Immunoelectron microscopy revealed that the CENH3 signals were associated with the nuclear envelope, implying interplay between the kinetochore complex and the nuclear envelope. These results demonstrate dynamic centromere reconstitution during the cell cycle in an organism in which the chromosomes do not condense at metaphase.
authors.affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-0032, Japan. maruyama@biol.s.u-tokyo.ac.jp
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Maruyama
authors.forename: Haruko
authors.initials: H
authors.lastname: Kuroiwa
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Miyagishima
authors.forename: Kan
authors.initials: K
authors.lastname: Tanaka
authors.forename: Tsuneyoshi
authors.initials: T
authors.lastname: Kuroiwa
mesh_terms: D000595:Amino Acid Sequence; D015415:Biomarkers / Q000378:metabolism; D002503:Centromere / Q000235:genetics* / Q000378:metabolism; D032461:Chromosomes, Plant; D015870:Gene Expression; D006657:Histones / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D000461:Rhodophyta / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions
chemical_list: D015415:Biomarkers; D006657:Histones