title: WRS-85D: A tryptophanyl-tRNA synthetase expressed to high levels in the developing Drosophila salivary gland.
abstract: In a screen for genes expressed in the Drosophila embryonic salivary gland, we identified a tryptophanyl-tRNA synthetase gene that maps to cytological position 85D (WRS-85D). WRS-85D expression is dependent on the homeotic gene Sex combs reduced (Scr). In the absence of Scr function, WRS-85D expression is lost in the salivary gland primordia; conversely, ectopic expression of Scr results in expression of WRS-85D in new locations. Despite the fact that WRS-85D is a housekeeping gene essential for protein synthesis, we detected both WRS-85D mRNA and protein at elevated levels in the developing salivary gland. WRS-85D is required for embryonic survival; embryos lacking the maternal contribution were unrecoverable, whereas larvae lacking the zygotic component died during the third instar larval stage. We showed that recombinant WRS-85D protein specifically charges tRNATrp, and WRS-85D is likely to be the only tryptophanyl-tRNA synthetase gene in Drosophila. We characterized the expression patterns of all 20 aminoacyl-tRNA synthetases and found that of the four aminoacyl-tRNA synthetase genes expressed at elevated levels in the salivary gland primordia, WRS-85D is expressed at the highest level throughout embryogenesis. We also discuss the potential noncanonical activities of tryptophanyl-tRNA synthetase in immune response and regulation of cell growth.
authors.affiliation: Department of Cell Biology and Anatomy, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA.
authors.forename: P
authors.initials: P
authors.lastname: Seshaiah
authors.forename: D J
authors.initials: DJ
authors.lastname: Andrew
mesh_terms: D000595:Amino Acid Sequence; D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D003001:Cloning, Molecular; D004330:Drosophila / Q000196:embryology / Q000201:enzymology*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D009154:Mutation; D012469:Salivary Glands / Q000196:embryology* / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D014369:Tryptophan-tRNA Ligase / Q000235:genetics* / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D000604:Amino Acyl-tRNA Synthetases; C119700:TrpRS protein, Drosophila; D014369:Tryptophan-tRNA Ligase