Format

Send to

Choose Destination
Chromosoma. 2007 Jun;116(3):259-74. Epub 2007 Feb 22.

Condensin I binds chromatin early in prophase and displays a highly dynamic association with Drosophila mitotic chromosomes.

Author information

1
Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.

Abstract

The condensed state of mitotic chromosomes is crucial for faithful genome segregation. Key factors implicated in the formation of mitotic chromosomes are the condensin I and II complexes. In Drosophila, condensin I appears to play a major role in mitotic chromosome organization. To analyze its dynamic behavior, we expressed Barren, a condensin I non-Structural Maintenance of Chromosomes subunit, as a fully functional enhanced green fluorescent protein (EGFP) fusion protein in the female and followed it during early embryonic divisions. We find that, in Drosophila, Barren-EGFP associates with chromatin early in prophase concomitantly with the initiation of chromosome condensation. Barren-EGFP loading starts at the centromeric region from where it spreads distally reaching maximum accumulation at metaphase/early anaphase. Fluorescence Recovery After Photobleaching analysis indicates that most of the bound protein exchanges rapidly with the cytoplasmic pool during prometaphase/metaphase. Taken together, our results suggest that in Drosophila, condensin I is involved in the initial stages of chromosome condensation. Furthermore, the rapid turnover of Barren-EGFP indicates that the mechanism by which condensin I promotes mitotic chromosome organization is inconsistent with a static scaffold model.

PMID:
17318635
DOI:
10.1007/s00412-007-0097-5
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center