FIG. 3.
T4 DNA polymerase treatment enhances LM-PCR detection of broken coding ends. (A to C) DNA samples prepared by the agarose plug method from uninduced (33°C [33 degr]) and induced (39°C [39 degr]) 103 bcl2/4 cells (A and B) and from newborn thymus (C) were analyzed by LM-PCR for broken Jκ1 coding (A), Jκ1 and Jκ2 signal (B), and JH2 coding and signal (C) ends without (lanes −) or with (lanes +) T4 DNA polymerase (T4 pol) pretreatment. Controls included identically prepared and treated 63-12 (RAG-2-deficient) cell DNA and buffer (lane C). DNA samples from panel C were amplified with primers specific for a nonrearranging genomic locus, demonstrating the presence of DNA in all samples. (D) Ethidium bromide-stained agarose gel of these control amplifications. Lanes 1 to 4 correspond to samples 1 to 4 in panel C, lanes 5 to 8 correspond to samples 6 to 9 in panel C, and lane 9 is a buffer-only control amplification. Lanes 1 to 6 of panels A and B were shown to contain equivalent amounts of DNA by a similar method (data not shown). ce, coding ends; se, signal ends.