Evolutionary recombination hotspot around GSDML-GSDM locus is closely linked to the oncogenomic recombination hotspot around the PPP1R1B-ERBB2-GRB7 amplicon

PPP1R1B-STARD3-TCAP-PNMT-PERLD1-ERBB2-MGC14832-GRB7 locus at human chromosome 17q12 is frequently amplified in human gastric cancer and breast cancer. Here, we compared human GSDML-GSDM locus with rodent genomes by using bioinformatics. Rodent ortholog of human GSDML was not identified. Rat Gsdm gene was identified within rat genome clone CH230-28N16 (AC119462.4), and was mapped to rat chromosome 10q31. Rat Gsdm gene, consisting of 12 exons, encoded a 446-amino-acid protein, which showed 86.3% and 32.3% total-amino-acid identities with human GSDM and GSDML, respectively. Mouse Gsdm-like 1 (Gsdml1) and Gsdml2 genes were identified within mouse genome clone RP23-438D7 (AL591125.20). Gsdml1 and Gsdml2 genes were found to encode 456- and 443-amino-acid proteins, respectively. Mouse 2200001G21Rik cDNA (AK008613.1) was a partial cDNA derived from mouse Gsdml2 gene. Mouse Gsdml1 and Gsdml2 were also more homologous to human GSDM than to human GSDML. Mouse Gsdml1, Gsdml2 and Gsdm genes, existing in the tandem homologous gene cluster, was mapped to mouse chromosome 11D. Mouse Gsdml1-Gsdml2-Gsdm gene cluster was predicted to be generated due to triplication of mouse Gsdm gene, while GSDML gene was predicted to be generated due to duplication of GSDM gene. Evolutionary recombination hotspot around the GSDML-GSDM locus was closely linked to the oncogenomic recombination hotspot around the PPP1R1B-ERBB2-GRB7 amplicon. The evolutionary recombination hotspot and oncogenomic recombination hotspot might be clustered around the fragile sites within the human genome.