title: Exploring features and function of Ss-riok-3, an enigmatic kinase gene from Strongyloides stercoralis.
abstract: BACKGROUND
  Right open reading frame protein kinase 3 (RIOK-3) belongs to the atypical kinase family. Unlike the other two members, RIOK-1 and RIOK-2, which are conserved from Archaea to humans, RIOK-3 occurs only in multicellular organisms. Studies on HeLa cells indicate that human RIOK-3 is a component of the 40S small ribosome subunit and supports cancer cell growth and survival. However, almost nothing is known about the function of RIOK-3. We explored the functional role of RIOK-3 encoding gene from Strongyloides stercoralis, a parasitic nematode of humans and dogs.
  
  
  METHODS
  To analyze the gene and promoter structure of Ss-riok-3, RACE-PCR and Genome-walker PCR were performed to isolate the full length cDNA, gDNA and promoter region of Ss-riok-3. RNA-seq was conducted to assess the transcript abundance of Ss-riok-3 in different stages of S. stercoralis. Transgenesis was employed to determine the anatomic expression patterns of Ss-riok-3.
  
  
  RESULTS
  The RIOK-3 protein-encoding gene (designated Ss-riok-3) of S. stercoralis was characterized. The full-length complementary and genomic DNAs of the RIOK-3 encoding gene (riok-3) were isolated from this nematode. The cDNA of Ss-riok-3 is 1,757 bp in length, including a 23 bp 5'-UTR, a 36 bp 3'-UTR and a 1,698 bp coding region encoding a protein of 565 amino acids (aa) containing a RIO kinase domain. RNA sequencing (RNA-seq) analysis revealed that Ss-riok-3 is transcribed in all developmental stages of S. stercoralis assessed, with transcripts being particularly abundant in parasitic females. Gene structure analysis revealed that Ss-riok-3 contains no intron. The putative promoter contains conserved promoter elements, including four TATA, two GATA, one inverse GATA and one inverse CAAT boxes. The promoter of Ss-riok-3 drives GFP expression in the head neuron, intestine and body wall muscle of transgenic S. stercoralis larvae, and the TATA boxes present in the 3'-UTR of the gene immediately upstream of Ss-riok-3 initiate transcription.
  
  
  CONCLUSIONS
  The characterization of the RIOK-3 encoding gene from S. stercoralis provides a sound foundation for investigating in detail its function in the development and reproduction of this important pathogen.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, 430070, China. ywang@webmail.hzau.edu.cn.
authors.forename: Wang
authors.initials: W
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, 430070, China. liu.yingying12@gmail.com.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA, 19104, USA. jlok@vet.upenn.edu.
authors.forename: James B
authors.initials: JB
authors.lastname: Lok
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA, 19104, USA. jonathan.stoltzfus@gmail.com.|Department of Biology, Hollins University, Roanoke, VI, 24020, USA. jonathan.stoltzfus@gmail.com.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Stoltzfus
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Corner of Flemington Road and Park Drive, Parkville, VI, 3010, Australia. robinbg@unimelb.edu.au.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Gasser
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, 430070, China. Leiweiqiang01@163.com.
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, 430070, China. fangrui19810705@163.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Fang
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, 430070, China. zhaojunlong@mail.hzau.edu.cn.
authors.forename: Junlong
authors.initials: J
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, College of Veterinary Medicine, Huazhong Agricultural University, 1 Shizishan Street, Wuhan, 430070, China. mhu@mail.hzau.edu.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Hu
mesh_terms: D000595:Amino Acid Sequence; D000825:Animal Structures / Q000201:enzymology; D000818:Animals; D016000:Cluster Analysis; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D020869:Gene Expression Profiling; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D016415:Sequence Alignment; D017385:Sequence Homology; D017171:Strongyloides stercoralis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
chemical_list: D018076:DNA, Complementary; D017346:Protein Serine-Threonine Kinases