Detection of a novel minisatellite-specific DNA-binding protein.

We describe the detection of a ubiquitous DNA-binding protein which appears to interact specifically with tandem-repeated minisatellites. The murine 40 kd protein, which we term Msbp-1, was found to be present in all mouse tissues tested. This protein was bound specifically and with high affinity by double-stranded DNA containing a repeat sequence related to the minisatellite 'core' sequence, and binding required the presence of multiple repeat units. Corresponding minisatellite-specific DNA-binding proteins could also be detected in species ranging from Drosophila to man. This analysis represents the first direct evidence that minisatellites can function as a specific recognition signal for an endogenous DNA-binding protein.