title: The budding yeast point centromere associates with two Cse4 molecules during mitosis.
abstract: The centromere is defined by the incorporation of the centromere-specific histone H3 variant centromere protein A (CENP-A). Like histone H3, CENP-A can form CENP-A-H4 heterotetramers in vitro. However, the in vivo conformation of CENP-A chromatin has been proposed by different studies as hemisomes, canonical, or heterotypic nucleosomes. A clear understanding of the in vivo architecture of CENP-A chromatin is important, because it influences the molecular mechanisms of the assembly and maintenance of the centromere and its function in kinetochore nucleation. A key determinant of this architecture is the number of CENP-A molecules bound to the centromere. Accurate measurement of this number can limit possible centromere architectures. The genetically defined point centromere in the budding yeast Saccharomyces cerevisiae provides a unique opportunity to define this number accurately, as this 120-bp-long centromere can at the most form one nucleosome or hemisome. Using novel live-cell fluorescence microscopy assays, we demonstrate that the budding yeast centromere recruits two Cse4 (ScCENP-A) molecules. These molecules are deposited during S phase and they remain stably bound through late anaphase. Our studies suggest that the budding yeast centromere incorporates a Cse4-H4 tetramer.
authors.affiliation: Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Pavithra
authors.initials: P
authors.lastname: Aravamudhan
authors.forename: Isabella
authors.initials: I
authors.lastname: Felzer-Kim
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Joglekar
mesh_terms: D000705:Anaphase; D001324:Autoantigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002503:Centromere / Q000378:metabolism*; D000076247:Centromere Protein A; D002843:Chromatin / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D018386:Kinetochores / Q000737:chemistry / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008938:Mitosis; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D001324:Autoantigens; D000076247:Centromere Protein A; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins