Fig. 2.

Deletion of V_H to D_H intergenic region leads increased germ-line transcription. Nuclear run-ons were conducted with nuclei from RAG2^−/− (^+/+) and RAG2^−/−(ΔV_H-D/ΔV_H-D) A-MuLV-transformed pro-B lines. ³²P-UTP–labeled nascent transcripts were hybridized to a series of double-stranded restriction endonuclease-generated DNA fragments (named on x axes) that were separated by electrophoresis and immobilized on Southern membranes. (A) The location of nuclear run-on probes (A through S) within the WT (Upper) and ΔV_H-D (Lower) IgH alleles is shown. (B) Schematic diagram of location of probe fragments in gels shown in C and D. Open squares depict backbone vector sequences, and filled squares depict IgH fragments/probes. (C and D) (Upper) Ethidium bromide–stained gel of Southern membrane. (Lower) Same membrane exposed after probing with labeled transcripts from RAG2^−/− (^+/+) (Left) and RAG2^−/−(ΔV_H-D/ΔV_H-D) (Right) A-MuLV-transformed pro-B lines. Results are representative of three independent experiments with different lines of the indicated genotype. See SI Materials and Methods for details.