Assembly of Drosophila centromeric chromatin proteins during mitosis.
PLoS Genet
; 7(5): e1002068, 2011 May.
Article
em En
| MEDLINE
| ID: mdl-21589899
ABSTRACT
Semi-conservative segregation of nucleosomes to sister chromatids during DNA replication creates gaps that must be filled by new nucleosome assembly. We analyzed the cell-cycle timing of centromeric chromatin assembly in Drosophila, which contains the H3 variant CID (CENP-A in humans), as well as CENP-C and CAL1, which are required for CID localization. Pulse-chase experiments show that CID and CENP-C levels decrease by 50% at each cell division, as predicted for semi-conservative segregation and inheritance, whereas CAL1 displays higher turnover. Quench-chase-pulse experiments demonstrate that there is a significant lag between replication and replenishment of centromeric chromatin. Surprisingly, new CID is recruited to centromeres in metaphase, by a mechanism that does not require an intact mitotic spindle, but does require proteasome activity. Interestingly, new CAL1 is recruited to centromeres before CID in prophase. Furthermore, CAL1, but not CENP-C, is found in complex with pre-nucleosomal CID. Finally, CENP-C displays yet a different pattern of incorporation, during both interphase and mitosis. The unusual timing of CID recruitment and unique dynamics of CAL1 identify a distinct centromere assembly pathway in Drosophila and suggest that CAL1 is a key regulator of centromere propagation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Cromatina
/
Centrômero
/
Mitose
Limite:
Animals
/
Humans
Idioma:
En
Revista:
PLoS Genet
Assunto da revista:
GENETICA
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Estados Unidos