RESTRICTION-ENDONUCLEASE RECOGNITION AND SOUTHERN HYBRIDIZATION OF BROMODEOXYURIDINE-SUBSTITUTED GENOMIC DNA

Human glioma cell lines exposed to various concentrations of bromodeox yuridine (BrdUrd) were studied to determine the effect of BrdUrd subst itution on restriction endonuclease recognition and Southern hybridiza tion of genomic DNA. BrdUrd substitution had no effect on the recognit ion of restriction endonucleases. When the exposure to BrdUrd was 2 h or less and the BrdUrd substitution rate was less than 40%, there was no difference in the density of hybridized bands after Southern hybrid ization using human non-recombinant complementary DNA as a probe. Hybr idization was suppressed significantly by exposures longer than 24 h o r BrdUrd substitution rates greater than 40%. These results suggest th at the BrdUrd substitution rate and the exposure time to BrdUrd influe nce the hybridization reaction by a DNA probe. Brief exposure (up to 2 h) to BrdUrd does not influence restriction endonuclease recognition or Southern hybridization of genomic DNA.