(Alliance, FBgn0002719 )

Structural gene for malic enzyme = (S)-Malate: NADP+ oxidoreductase [MEN (EC 1.1.1.40)], a tetramer with subunit molecular weight of 58,000 (Lee, Langley, and Burkhart, 1978, Anal. Biochem. 86: 697-296) or 67,250 (Geer, Krochko, Oliver, Walker, and Williamson, 1980, Comp. Biochem. Physiol. 65B: 25-34). Biochemical characterization by Geer, et al., (1980). Enzyme known to provide NADP for lipogenesis; levels in larvae increased by dietary carbohydrate and decreased by dietary lipid. Levels normally high in early third-instar larvae, reducing to half in late third instar, rising again in ageing adults. Highest specific activity found in larval fat body and, among cellular fractions, in the cytosol (Geer, Krochko, and Williamson, 1979, Biochem. Genet. 17: 867-79). Histochemical staining of larval imaginal discs reveals enzyme activity localized to nervous elements, including ommatidial precursors, the morphogenetic furrow, and the optic nerve in the eye antennal disc; and the chordotonal organ and the nerve traversing the leg discs; wing, haltere, labial, and genital discs unstained; however genital disc derivatives, the ejaculatory duct and paragonia in males and oviducts of females are stained in adults (Finkbohner, Cunningham, and Kuhn, 1985, Wilhelm Roux's Arch. Dev. Biol. 194: 217-23). Staining of morphogenetic groove absent in D. simulans and in simulans-melanogaster hybrids except when such hybrids contain two copies of 3R from D. melanogaster and none from D. simulans (Kuhn and Sprey, 1987, Genetics 115: 277-81). All null alleles tested survive and are fertile in combination with Df(3R)ry3l, which lacks Men+ (Voelker et al.). The NADPH/NADP ratio in such null genotypes is one-seventh that of wild type (Geer et al., 1979). Presence of an extra dose of the region from 8D10-12 to 9A1-2 results in an approximately 25% increase in MEN activity (Williamson and Bentley, 1983, Genetics 103: 649-58).