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Parra-Unda R, Vaca-Paniagua F, Jiménez L, Landa A. Cu,Zn superoxide dismutase: cloning and analysis of the Taenia solium gene and Taenia crassiceps cDNA. Exp Parasitol 2011; 130:32-8. [PMID: 22019409 DOI: 10.1016/j.exppara.2011.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 07/25/2011] [Accepted: 10/03/2011] [Indexed: 10/16/2022]
Abstract
Cytosolic Cu,Zn superoxide dismutase (Cu,Zn-SOD) catalyzes the dismutation of superoxide (O(2)(-)) to oxygen and hydrogen peroxide (H(2)O(2)) and plays an important role in the establishment and survival of helminthes in their hosts. In this work, we describe the Taenia solium Cu,Zn-SOD gene (TsCu,Zn-SOD) and a Taenia crassiceps (TcCu,Zn-SOD) cDNA. TsCu,Zn-SOD gene that spans 2.841 kb, and has three exons and two introns; the splicing junctions follow the GT-AG rule. Analysis in silico of the gene revealed that the 5'-flanking region has three putative TATA and CCAAT boxes, and transcription factor binding sites for NF1 and AP1. The transcription start site was a C, located at 22 nucleotides upstream of the translation start codon (ATG). Southern blot analysis showed that TcCu,Zn-SOD and TsCu,Zn-SOD genes are encoded by a single copy. The deduced amino acid sequences of TsCu,Zn-SOD gene and TcCu,Zn-SOD cDNA reveal 98.47% of identity, and the characteristic motives, including the catalytic site and β-barrel structure of the Cu,Zn-SOD. Proteomic and immunohistochemical analysis indicated that Cu,Zn-SOD does not have isoforms, is distributed throughout the bladder wall and is concentrated in the tegument of T. solium and T. crassiceps cysticerci. Expression analysis revealed that TcCu,Zn-SOD mRNA and protein expression levels do not change in cysticerci, even upon exposure to O(2)(-) (0-3.8 nmol/min) and H(2)O(2) (0-2mM), suggesting that this gene is constitutively expressed in these parasites.
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Affiliation(s)
- Ricardo Parra-Unda
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Edificio A, 2do Piso, Ciudad Universitaria, México DF 04510, Mexico
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SLO-1-channels of parasitic nematodes reconstitute locomotor behaviour and emodepside sensitivity in Caenorhabditis elegans slo-1 loss of function mutants. PLoS Pathog 2011; 7:e1001330. [PMID: 21490955 PMCID: PMC3072372 DOI: 10.1371/journal.ppat.1001330] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 03/04/2011] [Indexed: 11/24/2022] Open
Abstract
The calcium-gated potassium channel SLO-1 in Caenorhabditis elegans was recently identified as key component for action of emodepside, a new anthelmintic drug with broad spectrum activity. In this study we identified orthologues of slo-1 in Ancylostoma caninum, Cooperia oncophora, and Haemonchus contortus, all important parasitic nematodes in veterinary medicine. Furthermore, functional analyses of these slo-1 orthologues were performed using heterologous expression in C. elegans. We expressed A. caninum and C. oncophora slo-1 in the emodepside-resistant genetic background of the slo-1 loss-of-function mutant NM1968 slo-1(js379). Transformants expressing A. caninum slo-1 from C. elegans slo-1 promoter were highly susceptible (compared to the fully emodepside-resistant slo-1(js379)) and showed no significant difference in their emodepside susceptibility compared to wild-type C. elegans (p = 0.831). Therefore, the SLO-1 channels of A. caninum and C. elegans appear to be completely functionally interchangeable in terms of emodepside sensitivity. Furthermore, we tested the ability of the 5′ flanking regions of A. caninum and C. oncophora slo-1 to drive expression of SLO-1 in C. elegans and confirmed functionality of the putative promoters in this heterologous system. For all transgenic lines tested, expression of either native C. elegans slo-1 or the parasite-derived orthologue rescued emodepside sensitivity in slo-1(js379) and the locomotor phenotype of increased reversal frequency confirming the reconstitution of SLO-1 function in the locomotor circuits. A potent mammalian SLO-1 channel inhibitor, penitrem A, showed emodepside antagonising effects in A. caninum and C. elegans. The study combined the investigation of new anthelmintic targets from parasitic nematodes and experimental use of the respective target genes in C. elegans, therefore closing the gap between research approaches using model nematodes and those using target organisms. Considering the still scarcely advanced techniques for genetic engineering of parasitic nematodes, the presented method provides an excellent opportunity for examining the pharmacofunction of anthelmintic targets derived from parasitic nematodes. In parasitic nematodes, experiments at the molecular level are currently not feasible, since in vitro culture and genetic engineering are still in their infancy. In the present study we chose the model organism Caenorhabditis elegans not only as a mere expression system for genes from parasitic nematodes, but used the transformants to examine the functionality of the expressed proteins for mediating anthelmintic effects in vivo. The results of our experiments confirmed that SLO-1 channels mediate the activity of the new anthelmintic drug emodepside and showed that the mode of action is conserved through several nematode species. The chosen method allowed us to examine the functionality of proteins from parasitic nematodes in a defined genetic background. Notably, expression of the parasitic nematode gene in anthelmintic-resistant C. elegans completely restored drug susceptibility. As C. elegans is highly tractable to molecular genetic and pharmacological approaches, the generation of lines expressing the parasite drug target will greatly facilitate structure-function analysis of the interaction between emodepside and ion channels with direct relevance to its anthelmintic properties. In a broader context, the demonstration of C. elegans as a heterologous expression system for functional analysis of parasite proteins further strengthens this as a model for anthelmintic studies.
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Khare P, Mortimer SI, Cleto CL, Okamura K, Suzuki Y, Kusakabe T, Nakai K, Meedel TH, Hastings KEM. Cross-validated methods for promoter/transcription start site mapping in SL trans-spliced genes, established using the Ciona intestinalis troponin I gene. Nucleic Acids Res 2011; 39:2638-48. [PMID: 21109525 PMCID: PMC3074122 DOI: 10.1093/nar/gkq1151] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Revised: 10/22/2010] [Accepted: 10/25/2010] [Indexed: 11/12/2022] Open
Abstract
In conventionally-expressed eukaryotic genes, transcription start sites (TSSs) can be identified by mapping the mature mRNA 5'-terminal sequence onto the genome. However, this approach is not applicable to genes that undergo pre-mRNA 5'-leader trans-splicing (SL trans-splicing) because the original 5'-segment of the primary transcript is replaced by the spliced leader sequence during the trans-splicing reaction and is discarded. Thus TSS mapping for trans-spliced genes requires different approaches. We describe two such approaches and show that they generate precisely agreeing results for an SL trans-spliced gene encoding the muscle protein troponin I in the ascidian tunicate chordate Ciona intestinalis. One method is based on experimental deletion of trans-splice acceptor sites and the other is based on high-throughput mRNA 5'-RACE sequence analysis of natural RNA populations in order to detect minor transcripts containing the pre-mRNA's original 5'-end. Both methods identified a single major troponin I TSS located ∼460 nt upstream of the trans-splice acceptor site. Further experimental analysis identified a functionally important TATA element 31 nt upstream of the start site. The two methods employed have complementary strengths and are broadly applicable to mapping promoters/TSSs for trans-spliced genes in tunicates and in trans-splicing organisms from other phyla.
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Affiliation(s)
- Parul Khare
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Sandra I. Mortimer
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Cynthia L. Cleto
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Kohji Okamura
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Yutaka Suzuki
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Takehiro Kusakabe
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Kenta Nakai
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Thomas H. Meedel
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Kenneth E. M. Hastings
- Montreal Neurological Institute and Department of Biology, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4, Biology Department, Rhode Island College, Providence, RI 02908, USA, Human Genome Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokane-dai, Minato-ku, Tokyo, 108-8639 and Department of Biology, Faculty of Science and Engineering, Konan Univeristy, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
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