The Drosophila melanogaster gene for NADH:ubiquinone oxireductase acyl carrier protein: developmental expression analysis and evidence for alternatively spliced forms

We have isolated the Drosophila melanogastergene encoding the mitochondrial acyl carrier protein(mtACP), a subunit of NADH:ubiquinone oxidoreduc-tase involved in de novo fatty acid synthesis in the mi-tochondrion. This gene expresses two distinct maturetranscripts by alternative splicing, which encode maturepolypeptides of 86 (mtACP1A) and 88 (mtACP1B)amino acids, respectively. Drosophila mtACP1 is 72%identical to mammalian mtACP, 47% identical toArabidopsis thaliana mtACP, and 46% identical toNeurospora crassa mtACP. The most highly conservedregion encompasses the site that binds pantetheine-4¢-phosphate in all known ACPs. Southern analysis ofgenomic DNA and in situ hybridization to salivarygland chromosomes indicate that a single gene (mtacp1),located at 61F6±8, encodes the two isoforms of D. me-lanogaster mtACP1. Sequence analysis revealed that thegene contains four exons and that exons IIIA and IIIBare alternatively spliced. A P-element-induced loss-of-function mutation in the mtacp1 gene causes lethality,indicating that the gene is essential for viability. Devel-opmental Northern analysis shows that mtacp1 is ex-pressed at higher levels during late embryogenesis, in thepupa and in the adult. RNA in situ hybridization onembryos indicates that the mtacp1 gene is highly ex-pressed in the tracheal system. Zygotic mtacp1 functionis required for both male and female gametogenesis.