title: First insight into CD59-like molecules of adult Fasciola hepatica.
abstract: The present study focussed on investigating CD59-like molecules of Fasciola hepatica. A cDNA encoding a CD59-like protein (termed FhCD59-1) identified previously in the membrane fraction of the F. hepatica tegument was isolated. This homologue was shown to encode a predicted open reading frame (ORF) of 122 amino acids (aa) orthologous to human CD59 with a 25 aa signal peptide, a mature protein containing 10 cysteines and a conserved CD59/Ly-6 family motif "CCXXXXCN". An analysis of cDNAs from two different adult specimens of F. hepatica revealed seven variable types of FhCD59-1 sequences, designated FhCD59-1.1 to FhCD59-1.7, which had 94.3-99.7% amino acid sequence identity upon pairwise comparison. Molecular modeling of FhCD59-1.1 with human CD59 confirmed the presence of the three-finger protein domain found in the CD59 family and predicted three disulphide bonds in the F. hepatica sequence. The interrogation of F. hepatica databases identified two additional sequences, designated FhCD59-2 and FhCD59-3, which had only 23.4-29.5% amino acid identity to FhCD59-1.1. Orthologues of the inferred CD59 protein sequences of F. hepatica were also identified in other flatworms, including Fasciola gigantica, Fascioloides magna, Schistosoma haematobium, Schistosoma japonicum, Schistosoma mansoni, Clonorchis sinensis, Opisthorchis viverrini, Taenia solium, Echinococcus granulosus and the free living Schmidtea mediterannea. The results revealed a considerable degree of sequence complexity in the CD59-like sequence families in F. hepatica and flatworms. Phylogenetic analysis of CD59-like aa sequences from F. hepatica and flatworms showed that FhCD59-2 clustered with the known surface-associated protein SmCD59-2 of S. mansoni. Relatively well-supported clades specific to schistosomes, fasciolids and opisthorchiids were identified. The qPCR analysis of gene transcription showed that the relative expression of these 3 FhCD59-like sequences varied by 11-47-fold during fluke maturation, from the newly excysted juvenile (NEJ) to the adult stage. These findings suggest that different FhCD59-like sequences play distinct roles during the development of F. hepatica.
authors: College of Animal Science and Technology, Guangxi University, Nanning, Guangxi 530004, China; Department of Agricultural Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3086, Australia.
authors: Yunliang
authors: Y
authors: Shi
authors: Department of Agricultural Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3086, Australia.
authors: Hayley
authors: H
authors: Toet
authors: Department of Agricultural Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3086, Australia.
authors: Vignesh
authors: V
authors: Rathinasamy
authors: Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors: Neil D
authors: ND
authors: Young
authors: Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors: Robin B
authors: RB
authors: Gasser
authors: Department of Agricultural Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3086, Australia.
authors: Travis
authors: T
authors: Beddoe
authors: College of Animal Science and Technology, Guangxi University, Nanning, Guangxi 530004, China. Electronic address: wyhuang@gxu.edu.cn.
authors: Weiyi
authors: W
authors: Huang
authors: Department of Agricultural Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3086, Australia. Electronic address: t.spithill@latrobe.edu.au.
authors: Terry W
authors: TW
authors: Spithill
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018957:CD59 Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018509:DNA, Helminth / Q000737:chemistry / Q000302:isolation & purification; D005210:Fasciola hepatica / Q000145:classification / Q000235:genetics / Q000276:immunology*; D006801:Humans; D008958:Models, Molecular; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D051381:Rats; D016415:Sequence Alignment; D012756:Sheep
chemical_list: D018957:CD59 Antigens; D018509:DNA, Helminth
keywords: Adult fluke; CD59-like protein; Fasciola hepatica; Ly6 orthologue; Newly excysted juvenile (NEJ); Tegument proteins