Functional genomics identifies a Myb domain-containing protein family required for assembly of CENP-A chromatin.
Nucleosomes containing the centromere-specific histone H3 variant centromere protein A (CENP-A) create the chromatin foundation for kinetochore assembly. To understand the mechanisms that selectively target CENP-A to centromeres, we took a functional genomics approach in the nematode Caenorhabditis elegans, in which failure to load CENP-A results in a signature kinetochore-null (KNL) phenotype. We identified a single protein, KNL-2, that is specifically required for CENP-A incorporation into chromatin. KNL-2 and CENP-A localize to centromeres throughout the cell cycle in an interdependent manner and coordinately direct chromosome condensation, kinetochore assembly, and chromosome segregation. The isolation of KNL-2-associated chromatin coenriched CENP-A, indicating their close proximity on DNA. KNL-2 defines a new conserved family of Myb DNA-binding domain-containing proteins. The human homologue of KNL-2 is also specifically required for CENP-A loading and kinetochore assembly but is only transiently present at centromeres after mitotic exit. These results implicate a new protein class in the assembly of centromeric chromatin and suggest that holocentric and monocentric chromosomes share a common mechanism for CENP-A loading.
Maddox
Paul S
PS
Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
Hyndman
Francie
F
Monen
Joost
J
Oegema
Karen
K
Desai
Arshad
A
D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens / Q000235:genetics / Q000378:metabolism*; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*; D002503:Centromere / Q000378:metabolism; D000076247:Centromere Protein A; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D023281:Genomics; D006657:Histones / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000502:physiology*; D008969:Molecular Sequence Data; D005810:Multigene Family; D017434:Protein Structure, Tertiary; D020598:Proto-Oncogene Proteins c-myb / Q000737:chemistry; D034622:RNA Interference; D016415:Sequence Alignment
D001324:Autoantigens; C000619700:CENPA protein, human; D029742:Caenorhabditis elegans Proteins; D000076247:Centromere Protein A; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; C519207:KNL-2 protein, C elegans; D008869:Microtubule-Associated Proteins; D020598:Proto-Oncogene Proteins c-myb