DDP1, a Multi KH-Domain Protein of Drosophila, Associates to Pericentromeric Heterochromatin.
The centromeric dodeca-satellite of Drosophilaforms in vitro altered DNA structures in which its purine-rich strand forms stable fold-back structures while the complementary C-strand remains unstructured. DDP1 is a ssDNA binding protein that specifically binds the unstructured dodeca-satellite C-strand. In polytene chromosomes, DDP1 is found located at the chromocenter. During embryo development, DDP1 becomes nuclear after cellularisation, when heterochromatin is fully organised. In addition to its localisation at the chromocenter, in polytene chromosomes, DDP1 is also detected at several sites in the euchromatic arms co-localising with the heterochromatin protein HP1. DDP1 is a multi-KH domain protein homologous to the yeast Scp160 protein that is involved in the control of cell ploidy. Expression of DDP1 complements a Dscp160 deletion in yeast. The stoichiometry of the complexes formed with the dodeca-satellite C-strand suggests that, in DDP1, the 15 consecutive KH-domains are organized such that define two nucleic acid binding surfaces.
Cortes, A., and Azorin, F. (2000) Mol. Cell. Biol., in press
A. Cortes, D. Huertas, L. Fanti*, S. Pimpinelli*, F.X. Marsellach, B. Pina and F.Azorin
Departament de Biologia Molecular i Cellular.