A map of VH genes located next to the DH region in the Igh locus of two congenic Igh‐recombinant mouse strains

Abstract

A new congenic mouse strain (C57BL16‐Igh‐V^b‐C^a) with a recombinant chromosome 12 is described. It carries the Igh‐l^a allele, but shows the serological characteristics of C57BL/6 when analyzed for idiotype expression with respect to the antigens dextran and (4‐hydroxy‐5‐iodo‐3‐nitrophenyl)acetyl (NIP). We analyzed liver DNA from one animal for restriction fragment length polymorphism by hybridization to probes detecting members of nine V_H gene families and D_H segments, and compared it to DNA from animals carrying the nonrecombinant haplotypes Igh² and Igh^b, respectively. The breakpoint of recombination maps to the region carrying members of V_H gene families VGAM3.8, PC7183 and Q52. The CB8KN strain which according to the serological analysis carries a recombinant Igh locus (Igh‐V^a‐C^b) on BALB/c background was also analyzed. In this strain the breakpoint of recombination again maps to the region carrying members of V_H gene families VGAM3.8, PC7183 and Q52. Our results show that the V_H genes of families PC7183 and Q52 are interspersed and map to the region next to the D_H locus. At least one gene from the VGAM3.8 family also maps to this region in the Igh^a and the Igh^b haplotype.