title: Molecular characterization of the Haemonchus contortus phosphoinositide-dependent protein kinase-1 gene (Hc-pdk-1).
abstract: BACKGROUND
  Phosphoinositide-dependent protein kinase-1 (PDK-1), which functions downstream of phosphoinositide 3-kinase (AGE-1) and activates protein kinases of the AGC family, plays critical roles in regulating biology processes, such as metabolism, growth, development and survival. In the free-living nematode Caenorhabditis elegans, PDK-1 is a key component of the insulin-like signalling pathway, regulating the entry into and exit from dauer (arrested development). Although it is proposed that similar molecular mechanisms control the transition from the free-living to the parasitic stages of nematodes, nothing is known about PDK-1 in Haemonchus contortus, a socioeconomically important gastric nematode of ruminants.
  
  
  METHODS
  Here, we isolated and characterized the pdk-1 gene (Hc-pdk-1) and its inferred product (Hc-PDK-1) from H. contortus. Using in vitro and in vivo methods, we then studied the transcriptional profiles of Hc-pdk-1 and anatomical gene expression patterns of Hc-PDK-1 in different developmental stages of C. elegans.
  
  
  RESULTS
  In silico analysis of Hc-PDK-1 displayed conserved functional domains, such as protein kinase and pleckstrin homology (PH) domains and two predicted phosphorylation sites (Thr226/Tyr229), which are crucial for the phosphorylation of downstream signalling. The Hc-pdk-1 gene is transcribed in all of the main developmental stages of H. contortus, with its highest transcription in the infective third-stage larvae (iL3) compared with other stages. Transgene constructs, in which respective promoters were fused to the coding sequence for green fluorescent protein (GFP), were used to transform C. elegans, and to localize and compare the expression of Hc-pdk-1 and Ce-pdk-1. The expression of GFP under the control of the Hc-pdk-1 promoter was localized to the intestine, and head and tail neurons, contrasting somewhat the profile for the C. elegans ortholog, which is expressed in pharynx, intestine and head and tail neurons.
  
  
  CONCLUSIONS
  This is the first characterization of pdk-1/PDK-1 from a trichostrongyloid nematode. Taken together, the findings from this study provide a first glimpse of the involvement of Hc-pdk-1 in the insulin-like signalling pathway in H. contortus.
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. li78561270@163.com.
authors: Fa-Cai
authors: FC
authors: Li
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. robinbg@unimelb.edu.au.|Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia. robinbg@unimelb.edu.au.
authors: Robin B
authors: RB
authors: Gasser
authors: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA. jlok@vet.upenn.edu.
authors: James B
authors: JB
authors: Lok
authors: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia. pasi.korhonen@unimelb.edu.au.
authors: Pasi K
authors: PK
authors: Korhonen
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. 463771946@qq.com.
authors: Li
authors: L
authors: He
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. 732471543@qq.com.
authors: Wen-Da
authors: WD
authors: Di
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. yinfangyuan96@126.com.
authors: Fang-Yuan
authors: FY
authors: Yin
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. rzhou@mail.hzau.edu.cn.
authors: Rui
authors: R
authors: Zhou
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. yanqinzhou@mail.hzau.edu.cn.
authors: Yan-Qin
authors: YQ
authors: Zhou
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. zhaojunlong@mail.hzau.edu.cn.
authors: Jun-Long
authors: JL
authors: Zhao
authors: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. mhu@mail.hzau.edu.cn.
authors: Min
authors: M
authors: Hu
mesh_terms: D064413:3-Phosphoinositide-Dependent Protein Kinases / Q000235:genetics* / Q000302:isolation & purification*; D000818:Animals; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D020869:Gene Expression Profiling; D006189:Haemonchus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA
chemical_list: D018076:DNA, Complementary; D064413:3-Phosphoinositide-Dependent Protein Kinases