Trichostrongylus vitrinus (Nematoda: Strongylida): Molecular characterization and transcriptional analysis of Tv-stp-1, a serine/threonine phosphatase gene q Min Hu a,1 , Youssef G. Abs EL-Osta a,1 , Bronwyn E. Campbell a , Peter R. Boag b , Alasdair J. Nisbet c , Ian Beveridge a , Robin B. Gasser a, * a Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia b Joslin Diabetes Center, Harvard University, 1 Joslin Place, Boston, MA 02215, USA c Parasitology Division, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, Scotland Received 27 January 2007; received in revised form 2 March 2007; accepted 12 March 2007 Available online 24 March 2007 Abstract A full-length cDNA (Tv-stp-1) encoding a serine/threonine protein phosphatase (Tv-STP-1) was isolated from Trichostrongylus vit- rinus (order Strongylida), an economically important parasitic nematode of small ruminants. The uninterrupted open reading frame (ORF) of 951 nucleotides encoded a predicted protein of 316 amino acids (aa), containing the characteristic motif [LIVMN]-[KR]-G- N-H-E. Comparison with other sequences in non-redundant databases showed that Tv-STP-1 had significant identities/similarities to those from a range of metazoans and protists. Sequence similarity was most pronounced in the central region of the protein, in which the catalytic activity is inferred to be modulated by eight conserved residues (Asp 61, His 63, Asp 92, Asp 95, Asn 121, His 171, His 246 and Tyr 270), known to coordinate the binding of two metal ions (Mn 2+ and Fe 2+ ) in various organisms. Phylogenetic analyses of selected amino acid sequence data using the neighbor-joining and maximum parsimony methods revealed Tv-STP-1 to be most closely related to the glc seven-like phosphatases inferred for genes from the free-living nematode Caenorhabditis elegans and the parasitic nem- atode Oesophagostomum dentatum (order Strongylida). Comparison of the genomic organization of the full-length Tv-stp-1 gene with related molecules from other nematodes revealed substantial variation in the lengths and numbers of the exons and introns. The entire genes Tv-stp-1 (5041–5362 bp; 10 exons and 9 introns) and Od-mpp-1 (10,271 bp; 8 exons and 9 introns) from the parasitic nematodes T. vitrinus and O. dentatum were considerably longer than the C. elegans genes (1222–1603 bp; 3–7 exons and 2–6 introns). Transcriptional analysis by reverse transcription polymerase chain reaction (RT-PCR) showed that Tv-stp-1 was transcribed in adult males of T. vitrinus, but not in the adult female or in any larval stages of this species. In spite of considerable variation at the genomic level, the findings of the present study suggest that there is relative conservation in features and function of the serine/threonine protein phosphatase character- ized among T. vitrinus, O. dentatum and C. elegans, which should have implications for exploring molecular reproductive and develop- mental processes in strongylid nematodes of socio-economic importance. Ó 2007 Published by Elsevier Inc. Index Descriptors and Abbreviations: Serine-threonine protein phosphatase; Transcription; Genomic structure; Male-enriched; Nematode; Trichostron- gylus vitrinus; Caenorhabditis elegans 1. Introduction The phosphorylation/dephosphorylation of proteins is a fundamental post transcriptional process regulating their function. While protein kinases transfer a phosphate from ATP to a protein (i.e. phosphorylate), protein phosphatases (PPs) catalyse the removal of phosphate groups from 0014-4894/$ - see front matter Ó 2007 Published by Elsevier Inc. doi:10.1016/j.exppara.2007.03.008 q Note: Nucleotide sequence data reported in this paper are available in the EMBL, GenBank and DDJB databases under Accession Nos. AM691044–AM691049. * Corresponding author. Fax: +61 3 97312366. E-mail address: robinbg@unimelb.edu.au (R.B. Gasser). 1 These authors contributed equally to this work. www.elsevier.com/locate/yexpr Experimental Parasitology 117 (2007) 22–34