|
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129, USA
The Drosophila retinoblastoma family of proteins (RBF1 and RBF2) and their mammalian homologs (pRB, p130, and p107) are best known for their regulation of the G1/S transition via the repression of E2F-dependent transcription. However, RB family members also possess additional functions. Here, we report that rbf1 mutant larvae have extensive defects in chromatin condensation during mitosis. We describe a novel interaction between RBF1 and dCAP-D3, a non-SMC component of the Condensin II complex that links RBF1 to the regulation of chromosome structure. RBF1 physically interacts with dCAP-D3, RBF1 and dCAP-D3 partially colocalize on polytene chromosomes, and RBF1 is required for efficient association of dCAP-D3 with chromatin. dCap-D3 mutants also exhibit chromatin condensation defects, and mutant alleles of dCap-D3 suppress cellular and developmental phenotypes induced by the overexpression of RBF1. Interestingly, this interaction is conserved between flies and humans. The re-expression of pRB into a pRB-deficient human tumor cell line promotes chromatin association of hCAP-D3 in a manner that depends on the LXCXE-binding cleft of pRB. These results uncover an unexpected link between pRB/RBF1 and chromatin condensation, providing a mechanism by which the functional inactivation of RB family members in human tumor cells may contribute to genome instability.
[Keywords: RBF1; RB; CAP-D3; chromatin; condensation; Condensin II]]
Received November 6, 2007; revised version accepted February 7, 2008.
E-MAIL dyson{at}helix.mgh.harvard.edu; Fax (617) 726-7808.
Supplemental material is available at http://www.genesdev.org.
Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.1631508.
Related Article
![]()
CiteULike
Connotea
Del.icio.us
Digg
Reddit
Technorati What's this?
Genes & Dev. 2008 22: 964-969.
This article has been cited by other articles:
![]() |
B. D. Lavoie pRb and condensin--local control of global chromosome structure Genes & Dev., April 15, 2008; 22(8): 964 - 969. [Abstract] [Full Text] [PDF] |
||||