title: Post-transcriptional silencing and functional characterization of the Drosophila melanogaster homolog of human Surf1.
abstract: Mutations in Surf1, a human gene involved in the assembly of cytochrome c oxidase (COX), cause Leigh syndrome, the most common infantile mitochondrial encephalopathy, characterized by a specific COX deficiency. We report the generation and characterization of functional knockdown (KD) lines for Surf1 in Drosophila. KD was produced by post-transcriptional silencing employing a transgene encoding a dsRNA fragment of the Drosophila homolog of human Surf1, activated by the UAS transcriptional activator. Two alternative drivers, Actin5C-GAL4 or elav-GAL4, were used to induce silencing ubiquitously or in the CNS, respectively. Actin5C-GAL4 KD produced 100% egg-to-adult lethality. Most individuals died as larvae, which were sluggish and small. The few larvae reaching the pupal stage died as early imagos. Electron microscopy of larval muscles showed severely altered mitochondria. elav-GAL4-driven KD individuals developed to adulthood, although cephalic sections revealed low COX-specific activity. Behavioral and electrophysiological abnormalities were detected, including reduced photoresponsiveness in KD larvae using either driver, reduced locomotor speed in Actin5C-GAL4 KD larvae, and impaired optomotor response as well as abnormal electroretinograms in elav-GAL4 KD flies. These results indicate important functions for SURF1 specifically related to COX activity and suggest a crucial role of mitochondrial energy pathways in organogenesis and CNS development and function.
authors.affiliation: CNR Institute of Biomedical Technology, University of Padova, Padova, Italy.
authors.forename: Mauro A
authors.initials: MA
authors.lastname: Zordan
authors.forename: Paola
authors.initials: P
authors.lastname: Cisotto
authors.forename: Clara
authors.initials: C
authors.lastname: Benna
authors.forename: Alessandro
authors.initials: A
authors.lastname: Agostino
authors.forename: Giorgia
authors.initials: G
authors.lastname: Rizzo
authors.forename: Alberto
authors.initials: A
authors.lastname: Piccin
authors.forename: Mirko
authors.initials: M
authors.lastname: Pegoraro
authors.forename: Federica
authors.initials: F
authors.lastname: Sandrelli
authors.forename: Giuliana
authors.initials: G
authors.lastname: Perini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Tognon
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Caro
authors.forename: Samantha
authors.initials: S
authors.lastname: Peron
authors.forename: Truus Te
authors.initials: TT
authors.lastname: Kronniè
authors.forename: Aram
authors.initials: A
authors.lastname: Megighian
authors.forename: Carlo
authors.initials: C
authors.lastname: Reggiani
authors.forename: Massimo
authors.initials: M
authors.lastname: Zeviani
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Costa
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D051959:ELAV Proteins / Q000378:metabolism; D004594:Electrophysiology; D004596:Electroretinography; D005260:Female; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D005804:Genes, Lethal; D006801:Humans; D007814:Larva / Q000648:ultrastructure; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000502:physiology*; D009043:Motor Activity / Q000235:genetics / Q000502:physiology*; D009132:Muscles / Q000648:ultrastructure; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D034622:RNA Interference; D012323:RNA Processing, Post-Transcriptional; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D029721:Drosophila Proteins; D051959:ELAV Proteins; C498009:ELAV protein, Drosophila; C070633:Gal-VP16; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; C092928:Surf-1 protein; C000593793:Surf1 protein, Drosophila; D015534:Trans-Activators