Seymour Benzer

California Institute of Technology, Pasadena, California, United States

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Publications (100)1068.15 Total impact

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    Anne F Simon · Cindy Shih · Antha Mack · Seymour Benzer
    Full-text · Dataset · Aug 2015
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    Dataset: Figure S1
    [Show abstract] [Hide abstract] ABSTRACT: CG7598 is the D. melanogaster homolog of Ndufaf1/CIA30. (A) The D. melanogaster homolog of human Ndufaf1, CG7598 (dCIA30) was identified by homology. Amino acid sequence alignment shows 69% similarity (44% identity), concentrated near the C-terminal half, which contains the CIA30 domain. (B) CG7598 (dCIA30) maps to chromosome 3R at 99B9 and spans approximately 1.1 kb. The coding sequence consists of two exons separated by a 58 bp intron. A fly line with an insertion of an approximately 11 kb long P-element (P{EPgy2}) into the 5′UTR, 96 bp downstream from the transcriptional start site (dCIA30EY09101) was used for initial mutant studies. A line that contains a smaller insertion of approximately 500 bp was generated by imprecise excision of the transposable element (dCIA30ex80). A hairpin RNAi construct targeting the 325 bp of the first exon with no reported off target knock downs (UAS-dCIA30-IR) was used for RNAi knock down studies. (TIF)
    Preview · Dataset · Nov 2012
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    Dataset: Figure S2
    [Show abstract] [Hide abstract] ABSTRACT: Complex I loss due to dCIA30 mutation persists in adult flies. The dCIA30ex80 mutation results in specific loss of complex I holoenzyme band in BN-PAGE of adult male flies, 2 days post eclosion. In contrast, controls (+) and cDNA rescue flies show the presence of the complex I holoenzyme band. (M = molecular size marker, CV2 = complex V dimer, CI = complex I, CV1 = complex V monomer, CIII = complex III, CIV = complex IV, CII = complex II, 10, 25, 50 µg of total mitochondrial protein in successive lanes for each genotype). (TIF)
    Preview · Dataset · Nov 2012
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    Dataset: Figure S3
    [Show abstract] [Hide abstract] ABSTRACT: Expression of NDI1 does not affect complex I assembly. Expression of a UAS-Ndi1 construct does not affect the absence of the complex I holoenzyme band in a dCIA30ex80 mutant background. (M = molecular size marker, CV2 = complex V dimer, CI = complex I, CV1 = complex V monomer, CIII = complex III, CIV = complex IV, CII = complex II, mitochondria from 2.5, 5, and 10 larvae equivalents in successive lanes). (TIF)
    Preview · Dataset · Nov 2012
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    [Show abstract] [Hide abstract] ABSTRACT: Defects in mitochondrial electron transport chain (ETC) function have been implicated in a number of neurodegenerative disorders, cancer, and aging. Mitochondrial complex I (NADH dehydrogenase) is the largest and most complicated enzyme of the ETC with 45 subunits originating from two separate genomes. The biogenesis of complex I is an intricate process that requires multiple steps, subassemblies, and assembly factors. Here, we report the generation and characterization of a Drosophila model of complex I assembly factor deficiency. We show that CG7598 (dCIA30), the Drosophila homolog of human complex I assembly factor Ndufaf1, is necessary for proper complex I assembly. Reduced expression of dCIA30 results in the loss of the complex I holoenzyme band in blue-native polyacrylamide gel electrophoresis and loss of NADH:ubiquinone oxidoreductase activity in isolated mitochondria. The complex I assembly defect, caused by mutation or RNAi of dCIA30, has repercussions both during development and adulthood in Drosophila, including developmental arrest at the pupal stage and reduced stress resistance during adulthood. Expression of the single-subunit yeast alternative NADH dehydrogenase, Ndi1, can partially or wholly rescue phenotypes associated with the complex I assembly defect. Our work shows that CG7598/dCIA30 is a functional homolog of Ndufaf1 and adds to the accumulating evidence that transgenic NDI1 expression is a viable therapy for disorders arising from complex I deficiency.
    Full-text · Article · Nov 2012 · PLoS ONE
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    [Show abstract] [Hide abstract] ABSTRACT: Total food intake is a function of meal size and meal frequency, and adjustments to these parameters allow animals to maintain a stable energy balance in changing environmental conditions. The physiological mechanisms that regulate meal size have been studied in blowflies but have not been previously examined in Drosophila. Here we show that mutations in the leucokinin neuropeptide (leuc) and leucokinin receptor (lkr) genes cause phenotypes in which Drosophila adults have an increase in meal size and a compensatory reduction in meal frequency. Because mutant flies take larger but fewer meals, their caloric intake is the same as that of wild-type flies. The expression patterns of the leuc and lkr genes identify small groups of brain neurons that regulate this behavior. Leuc-containing presynaptic terminals are found close to Lkr neurons in the brain and ventral ganglia, suggesting that they deliver Leuc peptide to these neurons. Lkr neurons innervate the foregut. Flies in which Leuc or Lkr neurons are ablated have defects identical to those of leucokinin pathway mutants. Our data suggest that the increase in meal size in leuc and lkr mutants is due to a meal termination defect, perhaps arising from impaired communication of gut distension signals to the brain. Leucokinin and the leucokinin receptor are homologous to vertebrate tachykinin and its receptor, and injection of tachykinins reduces food consumption. Our results suggest that the roles of the tachykinin system in regulating food intake might be evolutionarily conserved between insects and vertebrates.
    Full-text · Article · Jun 2010 · Current biology: CB
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    [Show abstract] [Hide abstract] ABSTRACT: Methuselah (Mth) is a G protein-coupled receptor (GPCR) associated with longevity in Drosophila melanogaster. Previously, Stunted (Sun) was identified as a peptide agonist of Mth. Here, we identify two additional activators of Mth signaling: Drosophila Sex Peptide (SP) and a novel peptide (Serendipitous Peptide Activator of Mth, SPAM). Minimal functional sequences and key residues were identified from Sun and SPAM by studying truncation and alanine-scanning mutations. These peptide agonists share little sequence homology and illustrate the promiscuity of Mth for activation. mth mutants exhibit no defects in behaviors controlled by SP, casting doubt on the biological significance of Mth activation by any of these agonists, and illustrating the difficulty in applying in vitro studies to their relevance in vivo. Future studies of Mth ligands will help further our understanding of the functional interaction of agonists and GPCRs.
    Full-text · Article · Nov 2009 · Protein Science
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    [Show abstract] [Hide abstract] ABSTRACT: Dietary restriction (DR) is a widely conserved intervention leading to lifespan extension. Despite considerable effort, the mechanisms underlying DR remain poorly understood. In particular, it remains unclear whether DR prolongs life through conserved mechanisms in different species. Here, we show that, in the most common experimental conditions, lifespan extension by DR is abolished by providing Drosophila with ad libitum water, without altering food intake, indicating that DR, as conventionally studied in flies, is fundamentally different from the phenomenon studied in mammals. We characterize an alternative dietary paradigm that elicits robust lifespan extension irrespective of water availability, and thus likely represents a more relevant model for mammalian DR. Our results support the view that protein:carbohydrate ratio is the main dietary determinant of fly lifespan. These findings have broad implications for the study of lifespan and nutrition.
    Full-text · Article · Nov 2009 · Proceedings of the National Academy of Sciences
  • B. Al-Anzi · V. Sapin · C. Waters · K. Zinn · R.J. Wyman · S. Benzer
    No preview · Article · Oct 2009
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    [Show abstract] [Hide abstract] ABSTRACT: Dietary restriction (DR) extends lifespan in multiple species. To examine the mechanisms of lifespan extension upon DR, we assayed genome-wide translational changes in Drosophila. A number of nuclear encoded mitochondrial genes, including those in Complex I and IV of the electron transport chain, showed increased ribosomal loading and enhanced overall activity upon DR. We found that various mitochondrial genes possessed shorter and less structured 5'UTRs, which were important for their enhanced mRNA translation. The translational repressor 4E-BP, the eukaryotic translation initiation factor 4E binding protein, was upregulated upon DR and mediated DR dependent changes in mitochondrial activity and lifespan extension. Inhibition of individual mitochondrial subunits from Complex I and IV diminished the lifespan extension obtained upon DR, reflecting the importance of enhanced mitochondrial function during DR. Our results imply that translational regulation of nuclear-encoded mitochondrial gene expression by 4E-BP plays an important role in lifespan extension upon DR. For a video summary of this article, see the PaperFlick file with the Supplemental Data available online.
    Full-text · Article · Oct 2009 · Cell
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    [Show abstract] [Hide abstract] ABSTRACT: In mammals, fat store levels are communicated by leptin and insulin signaling to brain centers that regulate food intake and metabolism. By using transgenic manipulation of neural activity, we report the isolation of two distinct neuronal populations in flies that perform a similar function, the c673a-Gal4 and fruitless-Gal4 neurons. When either of these neuronal groups is silenced, fat store levels increase. This change is mediated through an increase in food intake and altered metabolism in c673a-Gal4-silenced flies, while silencing fruitless-Gal4 neurons alters only metabolism. Hyperactivation of either neuronal group causes depletion of fat stores by increasing metabolic rate and decreasing fatty acid synthesis. Altering the activities of these neurons causes changes in expression of genes known to regulate fat utilization. Our results show that the fly brain measures fat store levels and can induce changes in food intake and metabolism to maintain them within normal limits.
    Full-text · Article · Sep 2009 · Neuron
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    [Show abstract] [Hide abstract] ABSTRACT: Metabolic homeostasis in metazoans is regulated by endocrine control of insulin/IGF signaling (IIS) activity. Stress and inflammatory signaling pathways--such as Jun-N-terminal Kinase (JNK) signaling--repress IIS, curtailing anabolic processes to promote stress tolerance and extend lifespan. While this interaction constitutes an adaptive response that allows managing energy resources under stress conditions, excessive JNK activity in adipose tissue of vertebrates has been found to cause insulin resistance, promoting type II diabetes. Thus, the interaction between JNK and IIS has to be tightly regulated to ensure proper metabolic adaptation to environmental challenges. Here, we identify a new regulatory mechanism by which JNK influences metabolism systemically. We show that JNK signaling is required for metabolic homeostasis in flies and that this function is mediated by the Drosophila Lipocalin family member Neural Lazarillo (NLaz), a homologue of vertebrate Apolipoprotein D (ApoD) and Retinol Binding Protein 4 (RBP4). Lipocalins are emerging as central regulators of peripheral insulin sensitivity and have been implicated in metabolic diseases. NLaz is transcriptionally regulated by JNK signaling and is required for JNK-mediated stress and starvation tolerance. Loss of NLaz function reduces stress resistance and lifespan, while its over-expression represses growth, promotes stress tolerance and extends lifespan--phenotypes that are consistent with reduced IIS activity. Accordingly, we find that NLaz represses IIS activity in larvae and adult flies. Our results show that JNK-NLaz signaling antagonizes IIS and is critical for metabolic adaptation of the organism to environmental challenges. The JNK pathway and Lipocalins are structurally and functionally conserved, suggesting that similar interactions represent an evolutionarily conserved system for the control of metabolic homeostasis.
    Full-text · Article · May 2009 · PLoS Genetics
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    Gil B Carvalho · William W Ja · Seymour Benzer
    [Show abstract] [Hide abstract] ABSTRACT: In Drosophila, genetic techniques relying on stochastic chromosomal rearrangements involve the generation and screening of a large number of fly stocks to isolate a few lines of interest. Here, we describe a PCR-based method allowing non-lethal molecular characterization of single flies. Using this procedure, individual candidate recombinant animals can be genotyped and selected one generation earlier than with extant methodology and, importantly, before stocks are established. This advance should significantly facilitate several of the most fundamental and routine techniques in Drosophila genetics.
    Preview · Article · May 2009 · BioTechniques
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    Dataset: Figure S1
    [Show abstract] [Hide abstract] ABSTRACT: (A) Trehalose content in homogenates prepared from populations of 10 flies prior to and after 6, 24, and 30 hours of wet starvation. (A) hep1 and +/+. All measurements were normalized to the average weight of a single fly in its population. (B) Starvation sensitivity of hep1 mutant males in various genetic backgrounds. Males are progeny of crosses of hep1/FM6 to OreR (yellow n = 45), hep1/FM6 to w1118 (green n = 48) and hep1/FM6; pplG4/CyO to OreR (pink n = 40). Wild-type controls are progeny of OreR crossed to w1118. (C) Flies carrying the UAS-bskRNAi transgene in a wild-type background are not starvation sensitive. Sibling populations of progeny from crosses between w1118; UAS-bskRNAi/+ to w1118 are shown (w1118; +/+: n = 67, w1118; UAS-bskRNAi/+: n = 74). (D) dilp2, dilp3 and dilp5 transcript levels in hep1 mutants relative to +/+ controls determined by real time RT-PCR. All transcript levels were normalized to actin5C. No significant differences are observed in transcript levels of ILPs between hep1 and wild-type in ad libitum conditions. (E) No differences are observed in dilp2 transcript levels in starved flies. (0.7 MB TIF)
    Preview · Dataset · Apr 2009
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    Dataset: Figure S3
    [Show abstract] [Hide abstract] ABSTRACT: (A, B) Percent survival in response to dry starvation. Genotypes: (A) pplG4/+, n = 181, pplG4/+;UASKarl/+, n = 181. (B) hep1/y, n = 134, +/+, n = 130, hep1/y;DorothyG4/+;UASNLaz/+, n = 46. (0.4 MB TIF)
    Preview · Dataset · Apr 2009
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    Dataset: Figure S5
    [Show abstract] [Hide abstract] ABSTRACT: (A) Real time RT-PCR demonstrates that NLaz transcript levels are unchanged in chico1 heterozygous mutants. (B) Real time RT-PCR measuring levels of dilp2, dilp3, and dilp5 in cDNA prepared from dissected larval brains. Larval genotypes were as follows: +/+; NLazNW5/NW5; pplG4/+; pplG4/+;UASNLaz/+; pplG4/UASHep. Transcript levels were normalized to Actin5C. (C) Real time RT-PCR measuring levels of dilp2, dilp3, and dilp5 in adult heads from flies of the following genotypes: +/+, NLazNW5/NW5 pplG4/+, pplG4/+;UASNLaz/+, pplG4/UASHep. All transcript levels are normalized to Actin5C. (0.6 MB TIF)
    Preview · Dataset · Apr 2009
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    Dataset: Figure S7
    [Show abstract] [Hide abstract] ABSTRACT: NLaz is secreted. HA-tagged NLaz (lanes 1 and 2) can be detected in the medium of S2 cells after 6 hrs of conditioning. Cell pellet (P) and supernatant (S) are shown. Related lipocalins are also secreted: human ApoD (lanes 3 and 4) and Drosophila GLaz (lanes 5 and 6). (0.3 MB TIF)
    Preview · Dataset · Apr 2009
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    Dataset: Figure S6
    [Show abstract] [Hide abstract] ABSTRACT: NLaz over-expression from an alternative transgenic line promotes longevity. Overexpressing UAS-NLaz8, using DaG4 as a ubiquitous driver, increases mean and maximum lifespans in normal conditions.UAS-NLaz8/+, n = 108; DaG4/UAS-NLaz8, n = 92. Log-rank test: p<0.001. (0.2 MB TIF)
    Preview · Dataset · Apr 2009
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    Dataset: Figure S8
    [Show abstract] [Hide abstract] ABSTRACT: pplG4 is active in the adult fatbody. GFP fluorescence can be observed throughout the body of male and female adult flies when pplG4 is used to drive UAS-nlsGFP expression. This signal is derived from the head and abdominal fatbodies. Dissected abdominal fatbody is shown in the third panel. Ppl does not drive expression in ovaries (compare fluorescence in fatbody attached to cuticle and ovaries). (6.0 MB TIF)
    Preview · Dataset · Apr 2009
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    Dataset: Figure S2
    [Show abstract] [Hide abstract] ABSTRACT: (A) Real time RT-PCR to measure changes in transcription of selected potential secreted metabolic regulators in response to JNK activation. The heat shock-inducible TARGET system was utilized. Average fold induction (between Hepact expressing and wild-type controls) of non-heat shocked (reared at 18 degrees) and heat shocked samples are shown. Actin5C expression was used for normalization. (B) Transcriptional response of NLaz to JNK activation is not dependent on Foxo. Real time RT-PCR to measure changes in transcription of NLaz in larvae in which Hepact is over-expressed using the TARGET system. Reducing the Foxo genedose (dfoxo25 is a loss-of-function allele of dfoxo) does not affect the level of NLaz induction. (C) Over-expression of constitutively active Foxo (FoxoTM) is not sufficient to induce NLaz transcription. (D) Trehalose content of NLazNW5/NW5 compared to isogenic wild-type controls. (E) Flies carrying the UAS-NLaz transgene in a wild-type background are not starvation sensitive. Sibling populations of progeny from crosses between w1118;; UAS-NLaz/+ to w1118 are shown (w1118;; UAS-NLaz/+; n = 76, w1118;; +/+; n = 72). (F) Flies carrying the ppl-Gal4 transgene in a wild-type background are not starvation sensitive. Sibling populations of progeny from crosses between w1118; pplG4/+ to w1118; pplG4/+ are shown (w1118; pplG4/+; n = 66, w1118; pplG4/pplG4; n = 36; w1118; +/+; n = 36). (G) NLaz is induced in response to starvation in wild-types flies. NLaz transcript levels in adults of two wild-type strains (w1118 and CantonS) were measured by qRT-PCR. Prolonged (20 hr) starvation results in moderate increase of NLaz transcript. (0.5 MB TIF)
    Preview · Dataset · Apr 2009

Publication Stats

11k Citations
1,068.15 Total Impact Points

Institutions

  • 1976-2010
    • California Institute of Technology
      • Division of Biology
      Pasadena, California, United States
  • 2002
    • Boston Children's Hospital
      Boston, Massachusetts, United States
  • 1998
    • University of Pennsylvania
      • Department of Biology
      Philadelphia, Pennsylvania, United States
  • 1996
    • University of California, Los Angeles
      • Department of Medicine
      Los Angeles, CA, United States