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

The broad extension of an existing chemical DNA labeling technique for mole cular cytogenetics is described. Called the Universal Linkage System (ULS(T M)), it is based on the capability of monoreactive cisplatin derivatives to react at the N7 position of guanine moieties in DNA. Simple repetitive pro bes, 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 enzyma tically labeled probes. The advantage of ULS labeling over enzymatic labeli ng techniques is that it is a fast and simple procedure, and that the label ing 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 enzyma tic labeling is known to perform unsatisfactorily. Copyright (C) 1999 S. Ka rger AG, Basel.