Scm3 is essential to recruit the histone h3 variant cse4 to centromeres and to maintain a functional kinetochore.
The kinetochore is a complex multiprotein structure located at centromeres that is essential for proper chromosome segregation. Budding-yeast Cse4 is an essential evolutionarily conserved histone H3 variant recruited to the centromere by an unknown mechanism. We have identified Scm3, an inner kinetochore protein that immunopurifies with Cse4. Scm3 is essential for viability and localizes to all centromeres. Construction of a conditional SCM3 allele reveals that depletion results in metaphase arrest, with duplicated spindle poles, short spindles, and unequal DNA distribution. The metaphase arrest is mediated by the mitotic spindle checkpoint being dependent on Mad1 and the Aurora kinase B homolog Ipl1. Scm3 interacts with both Ndc10 and Cse4 and is essential to establish centromeric chromatin after DNA replication. In addition, Scm3 is required to maintain kinetochore function throughout the cell cycle. We propose a model in which Ndc10/Scm3 binds to centromeric DNA, which is in turn essential for targeting Cse4 to centromeres.
Camahort
Raymond
R
The Stowers Institute for Medical Research, 1000 E. 50th Street, Kansas City, MO 64110, USA.
Li
Bing
B
Florens
Laurence
L
Swanson
Selene K
SK
Washburn
Michael P
MP
Gerton
Jennifer L
JL
D064127:Aurora Kinases; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication / Q000502:physiology*; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D018386:Kinetochores; D008677:Metaphase / Q000502:physiology*; D008958:Models, Molecular; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism
C081071:CBF2 protein, S cerevisiae; C092746:CSE4 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D006657:Histones; C501382:MAD1 protein, S cerevisiae; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; C521684:Scm3 protein, S cerevisiae; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases