Molecular and functional analyses of the human and mouse genes encoding AFG3L1, a mitochondrial metalloprotease homologous to the human spastic paraplegia protein

The identification of SPG7 as the gene defective in a recessive form of spa stic paraplegia has drawn attention to the yeast protein family of ATP-depe ndent zinc metalloproteases. The protein encoded by SPG7, paraplegin, shows high homology to members of this protein family. Recently, many mammalian ATP-dependent zinc metalloproteases have been identified and considered as possible candidates for defects in other forms of hereditary spastic parapl egia and possibly other neurodegenerative disorders. So far only a partial sequence has been available for one of those genes, ATPase family gene-3, y east-like-1 (AFGM). We have carried out detailed molecular analysis of this gene and identified and characterized its mouse orthologue, Afg3L1. Our da ta indicate that AFG3L1 is transcribed into four mRNA isoforms that are not translated in humans. Afg3l1 encodes a protein with high homology to parap legin and the other members of the ATP-dependent zinc metalloprotease famil y. Like the other ATP-dependent zinc metalloproteases, Afg3l1 localizes to the mitochondria.