Description |
With this in mind, I undertook the problem of trying to isolate the DNA which was synthesized during the first one-hour and four-hour periods after disc incubation with B-ecdysone. I approached this by: 1) incubating the discs with 3H-BUdR for the appropriate times and subsequently isolating the DNA; 2) incubating Drosophila melanogaster cells of the Schneider line with 14C-thymidine for the period of at least two cell cycles and subsequently isolating the DNA; 3) by running the 3H-BUdR DNA and the 14C-thymidine DNA jointly in CsCl gradients in hopes that I could separate the two types of DNA since BUdR is a density label. If it is possible to separate and thereafter isolate the BUdR DNA by this technique, then what are the characteristics of this DNA, i.e., what are its Cot values and where on the chromosomes will it hybridize, as shown by in situ hybridization techniques? |