title: The Drosophila deoxyhypusine hydroxylase homologue nero and its target eIF5A are required for cell growth and the regulation of autophagy.
abstract: Hypusination is a unique posttranslational modification by which lysine is transformed into the atypical amino acid hypusine. eIF5A (eukaryotic initiation factor 5A) is the only known protein to contain hypusine. In this study, we describe the identification and characterization of nero, the Drosophila melanogaster deoxyhypusine hydroxylase (DOHH) homologue. nero mutations affect cell and organ size, bromodeoxyuridine incorporation, and autophagy. Knockdown of the hypusination target eIF5A via RNA interference causes phenotypes similar to nero mutations. However, loss of nero appears to cause milder phenotypes than loss of eIF5A. This is partially explained through a potential compensatory mechanism by which nero mutant cells up-regulate eIF5A levels. The failure of eIF5A up-regulation to rescue nero mutant phenotypes suggests that hypusination is required for eIF5A function. Furthermore, expression of enzymatically impaired forms of DOHH fails to rescue nero clones, indicating that hypusination activity is important for nero function. Our data also indicate that nero and eIF5A are required for cell growth and affect autophagy and protein synthesis.
authors: Program in Developmental Biology, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
authors: Prajal H
authors: PH
authors: Patel
authors: Mauro
authors: M
authors: Costa-Mattioli
authors: Karen L
authors: KL
authors: Schulze
authors: Hugo J
authors: HJ
authors: Bellen
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001343:Autophagy / Q000502:physiology*; D002453:Cell Cycle / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000201:enzymology* / Q000235:genetics; D055785:Gene Knockdown Techniques; D006899:Mixed Function Oxygenases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011499:Protein Processing, Post-Translational; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D029721:Drosophila Proteins; D006899:Mixed Function Oxygenases; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A; C047991:deoxyhypusine hydroxylase