Nucleotide sequence of F 0 -ATPase proteolipid (subunit 9) gene of maize mitochondria

The F0 -ATPase proteolipid, also referred to as subunit 9 or the dicyclohexylcarbodiimide-binding protein, is encoded by a mitochondrial gene in maize that we have designatedatp 9. The clone containingatp 9 was selected for investigation from a mitochondrial DNA library because of its abundant transcript in total maize mitochondrial RNA preparations. Sequence analysis of the clone revealed an open reading frame that was readily identified by its nucleotide homology with the ATPase subunit 9 gene of yeast. As deduced from the nucleotide sequence, the maize ATPase subunit 9 protein contains 74 amino acids with a molecular weight of 7368. Substantial amino acid sequence homology is conserved among maize, yeast, bovine, andNeurospora mitochondrial ATPase subunit 9 proteins, regardless of whether the gene is nuclearly encoded (bovine andNeurospora ) or mitochondrially encoded (yeast and maize). RNA transfer blot analysis indicated that the gene sequence is actively transcribed, producing an initial transcript that is large and extensively processed.