Figure 1. ψV Gene Deletion.

(A) Physical map of the rearranged Ig light chain locus in the chicken B-cell line DT40 and the ψV knockout constructs. The locus contains a total of 25 ψV genes upstream of the functional V segment. The strategy of knocking out ψV genes by the targeted integration of the pψVDel1-25 and the pψVDel3-25 constructs is shown. Only the relevant EcoRI sites are indicated.

(B) Southern blot analysis of wild-type and knockout clones using the probe shown in (A) after EcoRI digestion. The wild-type locus hybridizes as a 12-kb fragment, whereas ψV^partial and ψV^– loci hybridize as 7.4-kb and 6.3-kb fragments, respectively.

(C) AID status. The AID gene was amplified by PCR to verify the presence or absence of the AID cDNA expression cassette.