Aberrant replication timing induces defective chromosome condensation in Drosophila ORC2 mutants

Loupart, M.-L., Krause, S. A. and Heck, M. M.S. (2000) Aberrant replication timing induces defective chromosome condensation in Drosophila ORC2 mutants. Current Biology, 10(24), pp. 1547-1556. (doi: 10.1016/S0960-9822(00)00844-7) (PMID:11137005)

Full text not currently available from Enlighten.


Background: The accurate duplication and packaging of the genome is an absolute prerequisite to the segregation of chromosomes in mitosis. To understand the process of cell-cycle chromosome dynamics further, we have performed the first detailed characterization of a mutation affecting mitotic chromosome condensation in a metazoan. Our combined genetic and cytological approaches in Drosophila complement and extend existing work employing yeast genetics and Xenopusin vitro extract systems to characterize higher-order chromosome structure and function. Results: Two alleles of the ORC2 gene were found to cause death late in larval development, with defects in cell-cycle progression (delays in S-phase entry and metaphase exit) and chromosome condensation in mitosis. During S-phase progression in wild-type cells, euchromatin replicates early and heterochromatin replicates late. Both alleles disrupted the normal pattern of chromosomal replication, with some euchromatic regions replicating even later than heterochromatin. Mitotic chromosomes were irregularly condensed, with the abnormally late replicating regions of euchromatin exhibiting the greatest problems in mitotic condensation. Conclusions: The results not only reveal novel functions for ORC2 in chromosome architecture in metazoans, they also suggest that the correct timing of DNA replication may be essential for the assembly of chromatin that is fully competent to undergo mitotic condensation.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Krause, Dr Sue
Authors: Loupart, M.-L., Krause, S. A., and Heck, M. M.S.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Current Biology
Publisher:Elsevier (Cell Press)
ISSN (Online):1879-0445

University Staff: Request a correction | Enlighten Editors: Update this record