ISOLATION OF THE VMA-4 GENE ENCODING THE 26 KDA SUBUNIT OF THE NEUROSPORA-CRASSA VACUOLAR ATPASE

We have isolated the uma-4 gene, which encodes a 25 746 Dalton subunit of the vacuolar ATPase, from Neurospora crassa. The gene contains two introns and was mapped to the left arm of linkage group I. Comparison of the predicted amino acid sequence with homologous proteins from Sa ccharomyces cerevisiae, Manduca sexta, and Bos taurus showed only 25% sequence identity. However, computer-assisted predictions of secondary structures gave similar results for all four proteins. Analysis of th e sequence and the available biochemical data indicated that the uma-4 gene product may play the same structural role in the vacuolar ATPase as does the gamma-subunit in F-type ATPases.