Figure 3.
Mutant RAG1 constructs show deficient V(D)J recombination activity. A: Cellular recombination assays were performed using the plasmid substrate pSF200. V(D)J recombination of this substrate removes a transcription terminator allowing transcription of the CAT gene in bacterial cells.43 Precise signal formation introduces a new ApaLI restriction site in the recombined plasmid. B: Recombination activity was determined as described in Materials and Methods. In the first 5 lanes (n = 2 experiments), pSF200 was combined with GFP-core RAG1-expressing and GST-core RAG2-expressing constructs. In the last lane, Ch-FL-RAG2 was used in place of GST-core RAG2 to confirm that the cherry fusion does not impede RAG2 function.