Identification of a candidate gene for no mitochondrial derivative (nmd). S.T. Burke ¹, J.F. Sturgill ¹, N. Wolf ², M.T. Fuller ³, K.G. Hales ¹. 1) Department of Biology, Davidson College, Davidson, NC; 2) Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO; 3) Departments of Genetics and Developmental Biology, Stanford University, Stanford CA.

   We have identified a candidate gene for no mitochondrial derivative (nmd), which is required for mitochondrial aggregation during spermatogenesis. In wild type testes, mitochondria gather on the meiotic spindle, aggregate in post-meiotic spermatids, and subsequently fuse, and elongate beside the flagellar axoneme, perhaps to permit efficient delivery of ATP. The nmd mutation was generated through insertional mutagenesis with the P element P{ry11}. Homozygous mutant males are viable but sterile and show defective mitochondrial aggregation during meiosis and in post-meiotic spermatids. We used inverse PCR to obtain genomic DNA flanking the site of the P element insertion. The nmd P element is inserted in the 5' UTR of a previously uncharacterized predicted gene. The layout of the surrounding chromosomal landscape is such that the P element is unlikely to affect any other loci. Sequence analysis indicates that the product of the candidate nmd gene is a putative member of the AAA ATPase superfamily, with significant homology to a previously characterized yeast mitochondrial protein.