Molecular hybridization with RNA probes in concentrated solutions of guanidine thiocyanate.

Hybridizations with RNA probes were performed in 3-6 M guanidine thiocyanate concentrations where cells can be solubilized. At these concentrations the melting temperature of hybrids and the optimum temperature of hybrid formation are greatly reduced. The rate of hybridization in GuSCN at room temperature was greater than that in 50% formamide at 42 degrees C. Hybridizations were performed on DNA and RNA in cells dissolved in GuSCN without prior nucleic acid purification.