Deletion mapping of the mouse ornithine decarboxylase-related locus Odc-rs8 within Igh-V.

The Odc-rs8 locus belongs to a family of mouse DNA sequences related to the gene encoding ornithine decarboxylase (ODC). Odc-rs8 was mapped by recombinant inbred (RI) strain analysis to the region of Chromosome (Chr) 12 occupied by the variable region genes of the immunoglobulin heavy chain (Igh) complex. In the present study, alleles at Odc-rs8 were shown to cosegregate with those for Igh variable region (Igh-V or VH) genes among 37 inbred mouse strains that had been characterized previously for their haplotypes at Igh. For a more precise definition of the location of Odc-rs8 relative to Igh-V, DNAs from 17 Abelson murine leukemia virus (A-MuLV)-transformed pre-B cell lines cultured from mice heterozygous at Igh and Odc-rs8 were analyzed for the presence of DNA restriction fragments (RFs) derived from each parental Odc-rs8 allele. These cell lines, each of which has rearranged one or both Igh genes, previously were employed in mapping members of nine VH gene families by deletion analysis (Brodeur et al. 1988). Comparing the deletion profiles of the cell lines for Odc-rs8 with those for the VH gene families has located Odc-rs8b within the VHJ558/VH3609 gene cluster and Odc-rs8c either within or upstream of the 5'-most 9% of VHJ558, identifying Odc-rs8 as a potentially useful marker for the 5' end of the Igh complex.