Post-transcriptional silencing and functional characterization of the Drosophila melanogaster homolog of human Surf1.
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.
Zordan
Mauro A
MA
CNR Institute of Biomedical Technology, University of Padova, Padova, Italy.
Cisotto
Paola
P
Benna
Clara
C
Agostino
Alessandro
A
Rizzo
Giorgia
G
Piccin
Alberto
A
Pegoraro
Mirko
M
Sandrelli
Federica
F
Perini
Giuliana
G
Tognon
Giuseppe
G
De Caro
Raffaele
R
Peron
Samantha
S
Kronniè
Truus Te
TT
Megighian
Aram
A
Reggiani
Carlo
C
Zeviani
Massimo
M
Costa
Rodolfo
R
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
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