ULS: a versatile method of labeling nucleic acids for FISH based on a monofunctional reaction of cisplatin derivatives with guanine moieties

Abstract

The broad extension of an existing chemical DNA labeling technique for molecular cytogenetics is described. Called the Universal Linkage System (ULS^TM), it is based on the capability of monoreactive cisplatin derivatives to react at the N7 position of guanine moieties in DNA. Simple repetitive probes, cosmids, PACs, and chromosome-specific painting probes were labeled by ULS and used in a series of multicolor fluorescence in situ hybridization experiments on interphase and metaphase cells. It is demonstrated that ULS-labeled probes, in general, perform as well as the more conventional enzymatically labeled probes. The advantage of ULS labeling over enzymatic labeling techniques is that it is a fast and simple procedure, and that the labeling can easily be scaled up for bulk probe synthesis. In addition, with ULS labeling it is possible to label degraded DNA, a situation in which enzymatic labeling is known to perform unsatisfactorily.