Fission yeast Scm3: A CENP-A receptor required for integrity of subkinetochore chromatin.
The mechanisms ensuring specific incorporation of CENP-A at centromeres are poorly understood. Mis16 and Mis18 are required for CENP-A localization at centromeres and form a complex that is conserved from fission yeast to human. Fission yeast sim1 mutants that alleviate kinetochore domain silencing are defective in Scm3(Sp), the ortholog of budding yeast Scm3(Sc). Scm3(Sp) depends on Mis16/18 for its centromere localization and like them is recruited to centromeres in late anaphase. Importantly, Scm3(Sp) coaffinity purifies with CENP-A(Cnp1) and associates with CENP-A(Cnp1) in vitro, yet localizes independently of intact CENP-A(Cnp1) chromatin and is differentially released from chromatin. While Scm3(Sc) has been proposed to form a unique hexameric nucleosome with CENP-A(Cse4) and histone H4 at budding yeast point centromeres, we favor a model in which Scm3(Sp) acts as a CENP-A(Cnp1) receptor/assembly factor, cooperating with Mis16 and Mis18 to receive CENP-A(Cnp1) from the Sim3 escort and mediate assembly of CENP-A(Cnp1) into subkinetochore chromatin.
Pidoux
Alison L
AL
Wellcome Trust Centre for Cell Biology and Institute of Cell Biology, School of Biological Sciences, The University of Edinburgh, 6.34 Swann Building, Edinburgh EH93JR, Scotland, UK. alison.pidoux@ed.ac.uk
Choi
Eun Shik
ES
Abbott
Johanna K R
JK
Liu
Xingkun
X
Kagansky
Alexander
A
Castillo
Araceli G
AG
Hamilton
Georgina L
GL
Richardson
William
W
Rappsilber
Juri
J
He
Xiangwei
X
Allshire
Robin C
RC
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis / Q000378:metabolism*; D018386:Kinetochores / Q000378:metabolism*; D009154:Mutation; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C410349:Cnp1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins