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Barnes TM, Zupančič Ž, Burd NA. Swapping more dairy foods on our plates for a better breakfast. J Nutr 2024:S0022-3166(24)00231-1. [PMID: 38703892 DOI: 10.1016/j.tjnut.2024.04.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 04/11/2024] [Accepted: 04/20/2024] [Indexed: 05/06/2024] Open
Affiliation(s)
- Takeshi M Barnes
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Žan Zupančič
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Nicholas A Burd
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA; Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
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Paulussen KJM, Askow AT, Deutz MT, McKenna CF, Garvey SM, Guice JL, Kesler RM, Barnes TM, Tinker KM, Paluska SA, Ulanov AV, Bauer LL, Dilger RN, Burd NA. Acute Microbial Protease Supplementation Increases Net Postprandial Plasma Amino Acid Concentrations After Pea Protein Ingestion in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. J Nutr 2024:S0022-3166(24)00158-5. [PMID: 38467279 DOI: 10.1016/j.tjnut.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 03/13/2024] Open
Abstract
BACKGROUND Digestibility is a primary factor in determining the quality of dietary protein. Microbial protease supplementation may be a strategy for improving protein digestion and subsequent postprandial plasma amino acid availability. OBJECTIVES To assess the effect of co-ingesting a microbial protease mixture with pea protein on postprandial plasma amino acid concentrations. DESIGN A mixture of 3 microbial protease preparations (P3) was tested for proteolytic efficacy in an in vitro static simulation of gastrointestinal digestion. Subsequently, in a randomized, double-blind, placebo-controlled crossover trial, 24 healthy adults (27 ± 4 y; 12 females, 12 males) ingested 25 g pea protein isolate (20 g protein, 2.2 g fat) with either P3 or maltodextrin placebo (PLA). Blood samples were collected at baseline and throughout a 0‒5 h postprandial period and both the early (0-2 h) iAUC and total (0-5 h) iAUC were examined. RESULTS Plasma glucose concentrations decreased in both conditions (P < 0.001), with higher concentrations after P3 ingestion compared with PLA (P < 0.001). Plasma insulin concentrations increased for both conditions (P < 0.001) with no difference between conditions (P = 0.331). Plasma total amino acid (TAA) concentrations increased over time (P < 0.001) with higher concentrations observed for P3 compared with PLA (P = 0.010) during the 0‒5 h period. There was a trend for elevated essential amino acid (EAA) concentrations for P3 compared with PLA (P = 0.099) during the 0‒5 h postprandial period but not for leucine (P = 0.282) or branched-chain amino acids (BCAA, P = 0.410). The early net exposure (0‒2 h iAUC) to amino acids (leucine, BCAA, EAA, and TAA) was higher for P3 compared with PLA (all, P < 0.05). CONCLUSIONS Microbial protease co-ingestion increases plasma TAA concentrations (0-5 h) and leucine, BCAA, EAA, and TAA availability in the early postprandial period (0‒2 h) compared with ingesting pea protein with placebo in healthy adults.
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Affiliation(s)
- Kevin J M Paulussen
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Andrew T Askow
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Max T Deutz
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Colleen F McKenna
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Sean M Garvey
- Department of Research and Development, BIO-CAT, Inc., Troy, VA, United States
| | - Justin L Guice
- Department of Research and Development, BIO-CAT, Inc., Troy, VA, United States
| | - Richard M Kesler
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, IL, United States; Illinois Fire Service Institute, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Takeshi M Barnes
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Kelly M Tinker
- Department of Research and Development, BIO-CAT, Inc., Troy, VA, United States
| | - Scott A Paluska
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Alexander V Ulanov
- Roy J. Carver Biotechnology Center, University of Illinois Urbana-Champaign, Urbana, IL, States
| | - Laura L Bauer
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Ryan N Dilger
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States; Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Nicholas A Burd
- Department of Health and Kinesiology, University of Illinois Urbana-Champaign, Urbana, IL, United States; Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States.
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3
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Burd NA, Barnes TM, Moore DR. Reply to Anderson et al. J Nutr 2023; 153:3606-3607. [PMID: 37806356 DOI: 10.1016/j.tjnut.2023.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 09/27/2023] [Indexed: 10/10/2023] Open
Affiliation(s)
- Nicholas A Burd
- From the Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States; the Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States.
| | - Takeshi M Barnes
- From the Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Daniel R Moore
- the Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
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Paulussen KJ, Barnes TM, Askow AT, Salvador AF, McKenna CF, Scaroni SE, Fliflet A, Ulanov AV, Li Z, West DW, Bauer LL, Paluska SA, Dilger RN, Moore DR, Boppart MD, Burd NA. Underpinning the Food Matrix Regulation of Postexercise Myofibrillar Protein Synthesis by Comparing Salmon Ingestion With the Sum of Its Isolated Nutrients in Healthy Young Adults. J Nutr 2023; 153:1359-1372. [PMID: 36870539 DOI: 10.1016/j.tjnut.2023.02.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/28/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Protein is most commonly consumed as whole foods as opposed to single nutrients. However, the food matrix regulation of the postprandial muscle protein synthetic response has received little attention. OBJECTIVES The purpose of this study was to assess the effects of eating salmon (SAL) and of ingesting the same nutrients as an isolated mixture of crystalline amino acids and fish oil (ISO) on the stimulation of postexercise myofibrillar protein synthesis (MPS) and whole-body leucine oxidation rates in healthy young adults. METHODS Ten recreationally active adults (24 ± 4 y; 5 men, 5 women) performed an acute bout of resistance exercise, followed by the ingestion of SAL or ISO in a crossover fashion. Blood, breath, and muscle biopsies were collected at rest and after exercise during primed continuous infusions of L-[ring-2H5]phenylalanine and L-[1-13C]leucine. All data are presented as means ± SD and/or mean differences (95% CIs). RESULTS Postprandial essential amino acid (EAA) concentrations peaked earlier (P = 0.024) in the ISO group than those in the SAL group. Postprandial leucine oxidation rates increased over time (P < 0.001) and peaked earlier in the ISO group (1.239 ± 0.321 nmol/kg/min; 63 ± 25 min) than those in the SAL group (1.230 ± 0.561 nmol/kg/min; 105 ± 20 min; P = 0.003). MPS rates for SAL (0.056 ± 0.022 %/h; P = 0.001) and ISO (0.046 ± 0.025 %/h; P = 0.025) were greater than the basal rates (0.020 ± 0.011 %/h) during the 0- to 5-h recovery period, with no differences between conditions (P = 0.308). CONCLUSION We showed that the postexercise ingestion of SAL or ISO stimulate postexercise MPS rates with no differences between the conditions. Thus, our results indicate that ingesting protein from SAL as a whole-food matrix is similarly anabolic to ISO in healthy young adults. This trial was registered at www. CLINICALTRIALS gov as NCT03870165.
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Affiliation(s)
- Kevin Jm Paulussen
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Takeshi M Barnes
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Andrew T Askow
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Amadeo F Salvador
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Colleen F McKenna
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Susannah E Scaroni
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Alexander Fliflet
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Alexander V Ulanov
- Roy J. Carver Biotechnology Center, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Zhong Li
- Roy J. Carver Biotechnology Center, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Daniel Wd West
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada; KITE Research, Toronto Rehabilitation Institute, University of Toronto, Toronto, Ontario, Canada
| | - Laura L Bauer
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Scott A Paluska
- Department of Family Medicine, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Ryan N Dilger
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States; Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Daniel R Moore
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Nicholas A Burd
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, United States; Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States.
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Barnes TM, Deutz MT, Zupančič Ž, Askow AT, Moore DR, Burd NA. Protein quality and the food matrix: defining optimal versus maximal meal-based protein intakes for stimulating muscle protein synthesis. Appl Physiol Nutr Metab 2022; 48:340-344. [PMID: 36735923 DOI: 10.1139/apnm-2022-0373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This paper examines the opinion that we should aim to optimize, rather than maximize, protein intakes to avoid over-emphasizing muscle-centric protein requirements. An optimal eating approach strives to minimize amino acid oxidative waste and more efficiently stimulate postprandial muscle protein accretion. To do this, practitioners should acknowledge higher quality protein foods as better in delivering target amounts of amino acids into circulation, and the food matrix (e.g., nutrient-nutrient interactions) can be leveraged to potentiate essential amino acid incorporation into skeletal muscle protein.
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Affiliation(s)
- Takeshi M Barnes
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Max T Deutz
- Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Žan Zupančič
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Andrew T Askow
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Daniel R Moore
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | - Nicholas A Burd
- Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL, USA.,Division of Nutritional Sciences, University of Illinois Urbana-Champaign, Urbana, IL, USA
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Abstract
The 16s ribosomal tail end has been conjectured to play an important role in the regulation of protein production and of translation efficiency. Using E. coli K-12 as our model organism, we generate sequences of 13 base pairs as hypothetical ribosome tail ends. We analyzed the distributions of these random hypothetical ribosome tail ends and found the actual E. coli ribosome tail end to be significantly different from a randomly generated ribosome tail in the magnitude of the lock and synchronization signals, and the signal to noise ratio. We then designed and ran a genetic algorithm to optimize hypothetical ribosome tail ends simultaneously for these three signal criteria. We found that the actual E. coli ribosome tail end was among the best by these measures.
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Affiliation(s)
- L Ponnala
- Dept. of Electr. & Comput. Eng., North Carolina State Univ., Raleigh, NC, USA
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Abstract
Several loci have been identified in the nematode worm Caenorhabditis elegans that, when mutated, can increase life span. Three of these genes, age-1, daf-2 and clk-1, have now been cloned. Mutations in these three genes are highly pleiotropic and affect many aspects of worm development and behaviour, age-1 and daf-2 act in the same genetic pathway and have similar effects on the worm, age-1 encodes a homologue of the p110 subunit of phosphatidylinositol 3-kinase and daf-2 encodes an insulin receptor family member, clk-1 encodes a protein of unknown biochemical function similar to the yeast metabolic regulator Cat5p/Coq7p. The implications of these findings for our understanding of organismal ageing are discussed.
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Affiliation(s)
- S Hekimi
- Department of Biology, McGill University, Montréal, Québec, Canada.
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Barnes TM, Hekimi S. The Caenorhabditis elegans avermectin resistance and anesthetic response gene unc-9 encodes a member of a protein family implicated in electrical coupling of excitable cells. J Neurochem 1997; 69:2251-60. [PMID: 9375655 DOI: 10.1046/j.1471-4159.1997.69062251.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mutations in the unc-9 gene of the nematode Caenorhabditis elegans cause abnormal forward locomotion and an egg-retention phenotype. unc-9 mutations also reduce the worms' sensitivity to avermectin and block a form of hypersensitivity to volatile anesthetics. We report here the cloning and molecular characterization of unc-9 and show that it encodes a member of the OPUS family of proteins that is 56% identical to another OPUS protein, UNC-7. It is significant that unc-9 mutants share all phenotypes with unc-7 mutants. Mutants in another gene, unc-124, also share all tested phenotypes with unc-9 mutants, including identical locomotory and egg-laying defects, suggesting that multiple genes are required for the same biochemical function. OPUS proteins are implicated in the function of invertebrate gap junctions, and, based on a new alignment including 24 members from C. elegans, we present a refined model for the structure of OPUS proteins suggesting that oligomers could form a hydrophilic pore. We also show that alteration of highly conserved proline residues in UNC-9 leads to a cold sensitivity that likely affects a step in protein expression rather than function. Finally, we speculate on the basis of the avermectin resistance and anesthetic response phenotypes.
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Affiliation(s)
- T M Barnes
- Department of Biology, McGill University, Montréal, Québec, Canada
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Fleming JT, Squire MD, Barnes TM, Tornoe C, Matsuda K, Ahnn J, Fire A, Sulston JE, Barnard EA, Sattelle DB, Lewis JA. Caenorhabditis elegans levamisole resistance genes lev-1, unc-29, and unc-38 encode functional nicotinic acetylcholine receptor subunits. J Neurosci 1997; 17:5843-57. [PMID: 9221782 PMCID: PMC6573193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/1997] [Accepted: 05/14/1997] [Indexed: 02/04/2023] Open
Abstract
We show that three of the eleven genes of the nematode Caenorhabditis elegans that mediate resistance to the nematocide levamisole and to other cholinergic agonists encode nicotinic acetylcholine receptor (nAChR) subunits. unc-38 encodes an alpha subunit while lev-1 and unc-29 encode non-alpha subunits. The nematode nAChR subunits show conservation of many mammalian nAChR sequence features, implying an ancient evolutionary origin of nAChR proteins. Expression in Xenopus oocytes of combinations of these subunits that include the unc-38 alpha subunit results in levamisole-induced currents that are suppressed by the nAChR antagonists mecamylamine, neosurugatoxin, and d-tubocurarine but not alpha-bungarotoxin. The mutant phenotypes reveal that unc-38 and unc-29 subunits are necessary for nAChR function, whereas the lev-1 subunit is not. An UNC-29-GFP fusion shows that UNC-29 is expressed in body and head muscles. Two dominant mutations of lev-1 result in a single amino acid substitution or addition in or near transmembrane domain 2, a region important to ion channel conductance and desensitization. The identification of viable nAChR mutants in C. elegans provides an advantageous system in which receptor expression and synaptic targeting can be manipulated and studied in vivo.
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Affiliation(s)
- J T Fleming
- Laboratory of Molecular Biology, Medical Research Council Centre, Cambridge CB2 2QH, United Kingdom
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Ogura K, Shirakawa M, Barnes TM, Hekimi S, Ohshima Y. The UNC-14 protein required for axonal elongation and guidance in Caenorhabditis elegans interacts with the serine/threonine kinase UNC-51. Genes Dev 1997; 11:1801-11. [PMID: 9242488 DOI: 10.1101/gad.11.14.1801] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Certain unc mutants in the nematode Caenorhabditis elegans, such as unc-14 and unc-51, show abnormal axonal elongation and axonal structures. We cloned the unc-51 gene previously and predicted that it encodes a novel serine/threonine protein kinase. In this study, we precisely localized the activity to rescue an unc-14 mutation. Also, we identified four cDNA clones encoded by the unc-14 rescuing region, in screens for proteins that bind to UNC-51 using a yeast two-hybrid system. A mutation site in the cDNA was identified for each of the six unc-14 mutants, establishing that the unc-14 gene was cloned. The unc-14 gene encodes a novel protein of 665 amino acids, and is coexpressed with the unc-51 gene in the cell bodies and axons of almost all neurons including DD/VD and hermaphrodite-specific neurons. Another clone recovered in the two-hybrid screen encodes a carboxy-terminal region of UNC-51. Analysis using the yeast two-hybrid system suggested that a central region of UNC-14 bound to a carboxy-terminal region of UNC-51, and that the UNC-51 carboxy-terminal region oligomerized. In in vitro binding studies using recombinant fusion proteins, UNC-14 interacted with UNC-51 directly. We propose that UNC-51 protein kinase acts as an oligomer, and that UNC-14 is a regulator of UNC-51, in axonal elongation and guidance.
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Affiliation(s)
- K Ogura
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
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11
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Pflugrad A, Meir JY, Barnes TM, Miller DM. The Groucho-like transcription factor UNC-37 functions with the neural specificity gene unc-4 to govern motor neuron identity in C. elegans. Development 1997; 124:1699-709. [PMID: 9165118 DOI: 10.1242/dev.124.9.1699] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Groucho and Tup1 are members of a conserved family of WD repeat proteins that interact with specific transcription factors to repress target genes. Here we show that mutations in WD domains of the Groucho-like protein, UNC-37, affect a motor neuron trait that also depends on UNC-4, a homeodomain protein that controls neuronal specificity in Caenorhabditis elegans. In unc-4 mutants, VA motor neurons assume the pattern of synaptic input normally reserved for their lineal sister cells, the VB motor neurons; the loss of normal input to the VAs produces a distinctive backward movement defect. Substitution of a conserved residue (H to Y) in the fifth WD repeat in unc-37(e262) phenocopies the Unc-4 movement defect. Conversely, an amino acid change (E to K) in the sixth WD repeat of UNC-37 is a strong suppressor of unc-37(e262) and of specific unc-4 missense mutations. We have previously shown that UNC-4 expression in the VA motor neurons specifies the wild-type pattern of presynaptic input. Here we demonstrate that UNC-37 is also expressed in the VAs and that unc-37 activity in these neurons is sufficient to restore normal movement to unc-37(e262) animals. We propose that UNC-37 and UNC-4 function together to prevent expression of genes that define the VB pattern of synaptic inputs and thereby generate connections specific to the VA motor neurons. In addition, we show that the WD repeat domains of UNC-37 and of the human homolog, TLE1, are functionally interchangeable in VA motor neurons which suggests that this highly conserved protein domain may also specify motor neuron identity and synaptic choice in more complex nervous systems.
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Affiliation(s)
- A Pflugrad
- Department of Cell Biology, Vanderbilt University Medical Center, Nashville, TN 37232-2175, USA
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12
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Abstract
Mutations in the Caenorhabditis elegans gene clk-1 affect biological timing and extend longevity. The gene clk-1 was identified, and the cloned gene complemented the clk-1 phenotypes and restored normal longevity. The CLK-1 protein was found to be conserved among eukaryotes, including humans, and structurally similar to the yeast metabolic regulator Cat5p (also called Coq7p). These proteins contain a tandem duplication of a core 82-residue domain. clk-1 complemented the phenotype of cat5/coq7 null mutants, demonstrating that clk-1 and CAT5/COQ7 share biochemical function and that clk-1 acts at the level of cellular physiology.
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Affiliation(s)
- J J Ewbank
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, Québec, Canada H3A 1B1
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13
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Barnes TM, Hodgkin J. The tra-3 sex determination gene of Caenorhabditis elegans encodes a member of the calpain regulatory protease family. EMBO J 1996; 15:4477-84. [PMID: 8887539 PMCID: PMC452177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The Caenorhabditis elegans sex determination gene tra-3 is required for the correct sexual development of the soma and germ line in hermaphrodites, while being fully dispensable in males. Genetic analysis of tra-3 has suggested that its product may act as a potentiator of another sex determination gene, tra-2. Molecular analysis reported here reveals that the predicted tra-3 gene product is a member of the calpain family of calcium-regulated cytosolic proteases, though it lacks the calcium binding regulatory domain. Calpains are regulatory processing proteases, exhibiting marked substrate specificity, and mutations in the p94 isoform underlie the human hereditary condition limb-girdle muscular dystrophy type 2A. The molecular identity of TRA-3 is consistent with previous genetic analysis which suggested that tra-3 plays a very selective modulatory role and is required in very small amounts. Based on these observations and new genetic data, we suggest a refinement of the position of tra-3 within the sex determination cascade and discuss possible mechanisms of action for the TRA-3 protein.
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Affiliation(s)
- T M Barnes
- MRC Laboratory of Molecular Biology, Cambridge, UK
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14
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Barnes TM, Jin Y, Horvitz HR, Ruvkun G, Hekimi S. The Caenorhabditis elegans behavioral gene unc-24 encodes a novel bipartite protein similar to both erythrocyte band 7.2 (stomatin) and nonspecific lipid transfer protein. J Neurochem 1996; 67:46-57. [PMID: 8667025 DOI: 10.1046/j.1471-4159.1996.67010046.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We report here the positional cloning and molecular characterization of the unc-24 gene of Caenorhabditis elegans. This gene is required for normal locomotion and interacts with genes that affect the worm's response to volatile anesthetics. The predicted gene product contains a domain similar to part of two ion channel regulators (the erythrocyte integral membrane protein stomatin and the C. elegans neuronal protein MEC-2) juxtaposed to a domain similar to nonspecific lipid transfer protein (nsLTP; also called sterol carrier protein 2). Sequence analysis suggests that the nsLTP-like domain of UNC-24 provides lipid carrier function and is tethered to the plasma membrane by the stomatin-like domain which may be regulatory. We postulate that UNC-24 may be involved in lipid transfer between closely apposed membranes.
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Affiliation(s)
- T M Barnes
- Department of Biology, McGill University, Montréal, Québec, Canada
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15
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Abstract
The genetic map of each Caenorhabditis elegans chromosome has a central gene cluster (less pronounced on the X chromosome) that contains most of the mutationally defined genes. Many linkage group termini also have clusters, though involving fewer loci. We examine the factors shaping the genetic map by analyzing the rate of recombination and gene density across the genome using the positions of cloned genes and random cDNA clones from the physical map. Each chromosome has a central gene-dense region (more diffuse on the X) with discrete boundaries, flanked by gene-poor regions. Only autosomes have reduced rates of recombination in these gene-dense regions. Cluster boundaries appear discrete also by recombination rate, and the boundaries defined by recombination rate and gene density mostly, but not always, coincide. Terminal clusters have greater gene densities than the adjoining arm but similar recombination rates. Thus, unlike in other species, most exchange in C. elegans occurs in gene-poor regions. The recombination rate across each cluster is constant and similar; and cluster size and gene number per chromosome are independent of the physical size of chromosomes. We propose a model of how this genome organization arose.
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Affiliation(s)
- T M Barnes
- Department of Biology, McGill University, Montréal, Quebec, Canada
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Abstract
The normal form of the nematode Caenorhabditis elegans is a self-fertilizing hermaphrodite, which produces from the same germ-line tissue first a limited number of sperm and then a larger number of oocytes. Self-progeny brood sizes are determined by the number of sperm, and most of the oocytes remain unfertilized. Therefore it might seem selectively advantageous to increase the number of sperm, and hence the size of the brood. A mutation that leads to a 50% increase in sperm production allows a comparison of population growth rates between the wild type (mean brood 327 progeny) and the mutant (mean brood 499 progeny). Wild-type populations grow faster, as measured by food consumption, indicating that increased brood size is not advantageous. The mutant appears to be at a disadvantage because the additional spermatogenesis leads to a delay in the onset of oogenesis, and hence to an increase in the minimum generation time. In support of the notion of an optimal brood size, it was found that different natural isolates of this species have self-fertilities similar to that of the standard laboratory strain, in the range 250-350 progeny per worm.
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Affiliation(s)
- J Hodgkin
- MRC Laboratory of Molecular Biology, Cambridge, U.K
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Affiliation(s)
- T M Barnes
- MRC Laboratory of Molecular Biology, Cambridge, UK
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Affiliation(s)
- T M Barnes
- MRC Laboratory of Molecular Biology, Cambridge, UK
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