Mouse mitochondrial superoxide dismutase locus is on chromosome 17

The hamster X mouse hybridoma cell line GCL28 carries only one copy of mouse chromosome 17 but expresses H-2 antigens controlled by the major histocompatibility complex of the mouse. The cell line and clones derived from it were subjected to treatment with H-2 specific antisera and complement and a series of H-2 antigen-negative clones was produced. Typing of the clones for the mouse enzyme glyoxalase 1, which is encoded by an H-2-linked gene, revealed that the loss of H-2 antigen expression was accompanied by the loss of chromosomes 17 in these clones. This suggestion was verified by karyotype analysis of selected clones. Typing of the clones and subclones for the mouse mitochondrial superoxide dismutase (SOD-2) indicated complete concordance between loss of chromosome 17 and loss of SOD-2 activity. This finding suggests that the locus controlling the expression of SOD-2 is located on chromosome 17. Since a similar locus in the human is linked to HLA, the human major histocompatibility complex, extensive homology must exist between the mouse and human MHC-bearing chromosomes.