The N-terminal tail of C. elegans CENP-A interacts with KNL-2 and is essential for centromeric chromatin assembly.
Mol Biol Cell
; 32(12): 1193-1201, 2021 06 01.
Article
em En
| MEDLINE
| ID: mdl-33852350
ABSTRACT
Centromeres are epigenetically defined by the centromere-specific histone H3 variant CENP-A. Specialized loading machinery, including the histone chaperone HJURP/Scm3, participates in CENP-A nucleosome assembly. However, Scm3/HJURP is missing from multiple lineages, including nematodes, with CENP-A-dependent centromeres. Here, we show that the extended N-terminal tail of Caenorhabditis elegans CENP-A contains a predicted structured region that is essential for centromeric chromatin assembly; removal of this region prevents CENP-A loading, resulting in failure of kinetochore assembly and defective chromosome condensation. By contrast, the N-tail mutant CENP-A localizes normally in the presence of endogenous CENP-A. The portion of the N-tail containing the predicted structured region binds to KNL-2, a conserved SANTA domain and Myb domain-containing protein (referred to as M18BP1 in vertebrates) specifically involved in CENP-A chromatin assembly. This direct interaction is conserved in the related nematode Caenorhabditis briggsae, despite divergence of the N-tail and KNL-2 primary sequences. Thus, the extended N-tail of CENP-A is essential for CENP-A chromatin assembly in C. elegans and partially substitutes for the function of Scm3/HJURP, in that it mediates a direct interaction between CENP-A and KNL-2. These results highlight an evolutionary variation on centromeric chromatin assembly in the absence of a dedicated CENP-A-specific chaperone/targeting factor of the Scm3/HJURP family.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Centrômero
/
Caenorhabditis elegans
/
Proteínas de Caenorhabditis elegans
/
Proteína Centromérica A
/
Proteínas Associadas aos Microtúbulos
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
Mol Biol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2021
Tipo de documento:
Article