Open AccessBinding of Drosophila Orc Proteins to Anaphase Chromosomes Requires Cessation of Mitotic Cyclin-Dependent Kinase Activity
Author(s) -
Tina Baldinger,
Manfred Gossen
Publication year - 2009
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.00981-08
Subject(s) - biology , anaphase , microbiology and biotechnology , mitosis , cyclin b , genetics , cyclin , cell cycle , gene
The initial step in the acquisition of replication competence by eukaryotic chromosomes is the binding of the multisubunit origin recognition complex, ORC. We describe a transgenicDrosophila model which enables dynamic imaging of a green fluorescent protein (GFP)-taggedDrosophila melanogaster ORC subunit, DmOrc2-GFP. It is functional in genetic complementation, expressed at physiological levels, and participates quantitatively in complex formation. This fusion protein is therefore able to depict both the holocomplex DmOrc1-6 and the core complex DmOrc2-6 formed by theDrosophila initiator proteins. Its localization can be monitored in vivo along the cell cycle and development. DmOrc2-GFP is not detected on metaphase chromosomes but binds rapidly to anaphase chromatin inDrosophila embryos. Expression of either stable cyclin A, B, or B3 prevents this reassociation, suggesting that cessation of mitotic cyclin-dependent kinase activity is essential for binding of the DmOrc proteins to chromosomes.