Identification, characterization, and mapping of a mouse homolog of the gene mutated in Nijmegen breakage syndrome.

The rare autosomal recessive disorder Nijmegen breakage syndrome (NBS) results from mutations in the NBS1 gene on human chromosome 8q21. A mouse homolog of the NBS1 gene was isolated and its nucleotide sequence determined. Somatic cell hybrid analysis and fluorescence in situ hybridization were used to map this gene, Nbn, to mouse chromosome band 4A. Northern blotting revealed comparable levels of Nbn transcripts in most tissues in the mouse. However, transcripts were elevated 10-20 fold in the testes, consistent with a possible role for the product of the Nbn gene in meiotic recombination.