title: GTP-cyclohydrolase and development in Teladorsagia circumcincta and Dictyocaulus viviparus (Nematoda: Strongylida).
abstract: GTP-Cyclohydrolase (GTP-CH) is necessary for the production of tetrahydrobiopterin, a required cofactor for the three aromatic amino acid hydroxylases and nitric oxide synthases. The gene encoding GTP-CH is transcribed at high levels in infective third larval stages of a number of parasitic trichostrongylid nematodes. We explore the potential role of GTP-CH within the processes of nematode development and environmentally-induced hypobiosis. For two species of parasitic nematode that are of major economic and welfare importance to livestock in temperate regions, Teladorsagia circumcincta and Dictyocaulus viviparus, we have demonstrated that each of the pre-parasitic larval stages transcribe high mean levels of cat-4 (the gene encoding GTP-CH). Using quantitative real-time polymerase chain reaction analysis and two different isolates of D. viviparus, only one of which is capable of entering hypobiosis, we have shown that there were only minor differences between these isolates in mean cat-4 transcript levels, both during the parasitic stages and during the earlier environmental life cycle stages (L(1)-L(3)). Taken together, these data indicate that, although both species of nematode produce high levels of cat-4 transcript in pre-parasitic larval stages, GTP-CH levels are unlikely to be involved in the induction of parasite hypobiosis. Alternative roles for GTP-CH in larval development are discussed.
authors.affiliation: Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh EH26 0PZ, UK. Rachael.Baker@moredun.ac.uk
authors.forename: Rachael H
authors.initials: RH
authors.lastname: Baker
authors.forename: Sandra
authors.initials: S
authors.lastname: Buschbaum
authors.forename: Jacqueline B
authors.initials: JB
authors.lastname: Matthews
authors.forename: Iain J
authors.initials: IJ
authors.lastname: McKendrick
authors.forename: Thomas
authors.initials: T
authors.lastname: Schnieder
authors.forename: Christina
authors.initials: C
authors.lastname: Strube
authors.forename: Alasdair J
authors.initials: AJ
authors.lastname: Nisbet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D018076:DNA, Complementary / Q000737:chemistry; D004021:Dictyocaulus / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D004587:Electrophoresis, Agar Gel; D005260:Female; D006136:GTP Cyclohydrolase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D049751:Genome, Helminth; D007814:Larva / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D008297:Male; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D018510:RNA, Helminth / Q000235:genetics / Q000302:isolation & purification; D016415:Sequence Alignment; D012756:Sheep; D014158:Transcription, Genetic; D014251:Trichostrongyloidea / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*
chemical_list: D018076:DNA, Complementary; D018510:RNA, Helminth; D006136:GTP Cyclohydrolase