DNA topology, not DNA sequence, is a critical determinant for Drosophila ORC-DNA binding.

ABSTRACT: Drosophila origin recognition complex (ORC) localizes to defined positions on chromosomes, and in follicle cells the chorion gene amplification loci are well-studied examples. However, the mechanism of specific localization is not known. We have studied the DNA binding of DmORC to investigate the cis-requirements for DmORC:DNA interaction. DmORC displays at best six-fold differences in the relative affinities to DNA from the third chorion locus and to random fragments in vitro, and chemical probing and DNase1 protection experiments did not identify a discrete binding site for DmORC on any of these fragments. The intrinsic DNA-binding specificity of DmORC is therefore insufficient to target DmORC to origins of replication in vivo. However, the topological state of the DNA significantly infl

SUBMITTER: Remus D 

PROVIDER: S-EPMC380993 | biostudies-literature | 2004 Feb

REPOSITORIES: biostudies-literature