Functional genomics identifies a Myb domain-containing protein family required for assembly of CENP-A chromatin

J Cell Biol. 2007 Mar 12;176(6):757-63. doi: 10.1083/jcb.200701065. Epub 2007 Mar 5.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Autoantigens / genetics
  • Autoantigens / metabolism*
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans Proteins / antagonists & inhibitors
  • Caenorhabditis elegans Proteins / chemistry
  • Caenorhabditis elegans Proteins / physiology*
  • Centromere / metabolism
  • Centromere Protein A
  • Chromatin / metabolism*
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Genomics
  • Histones / metabolism
  • Microtubule-Associated Proteins / antagonists & inhibitors
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / physiology*
  • Molecular Sequence Data
  • Multigene Family*
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins c-myb / chemistry
  • RNA Interference
  • Sequence Alignment


  • Autoantigens
  • CENPA protein, human
  • Caenorhabditis elegans Proteins
  • Centromere Protein A
  • Chromatin
  • Chromosomal Proteins, Non-Histone
  • Histones
  • KNL-2 protein, C elegans
  • Microtubule-Associated Proteins
  • Proto-Oncogene Proteins c-myb