LABELING OF RNA TRANSCRIPTS OF EUKARYOTIC CELLS IN CULTURE WITH BRUTPUSING A LIPOSOME TRANSFECTION REAGENT (DOTAP(R))

Bromouridine-triphosphate (BrUTP), when introduced into eukaryotic cel ls in culture, substitutes for UTP during transcription, thereby label ing pre-mRNA for detection by immunochemical methods. In detection by immunochemical methods. In earlier studies, BrUTP was internalized by means of microinjection or by exposing isolated nuclei or permeable ce lls to BrUTP. We describe here a simple method for the extensive uptak e of BrUTP into monolayers of growing cells using a cationic liposome transfectant (DOTAP(R)). Within minutes, DOTAP mediates uptake of BrUT P both at 37 degrees and 4 degrees C. This is followed by incorporatio n into RNA in the nucleus upon further incubation under culture condit ions. In this way, large numbers of actively growing cells may be subj ected to biochemical experiments.