Characterization of follistatin-related protein from the hard tick Haemaphysalis longicornis / 生物工程学报

We designed the primers based on the sequence of the follistatin-related protein from Haemaphysalis longicornis Okayama strain accessed in GenBank. We cloned a gene encoding follistatin-related protein by RT-PCR, and the length cDNA is 814 bp, encoding a deduced protein of 289 amino acids. The alignment with the sequence of follistatin-related protein from the H. longicornis Okayama strain showed that the percent of nucleotide sequence and amino acid sequence is 97.8% and 99%, respectively. The expected size of GST-fused recombinant protein was 57 kD. We purified the recombinant protein through MagneGST protein purification system. Western blotting revealed that stronger reaction happened with the antiserum against eggs, but not clear with antisera against other developmental stages.

Construction of cDNA Expression Library of Unfed Female Haemaphysalis longicornis and Immuno-Screening / 中国寄生虫学与寄生虫病杂志

Objective To construct a cDNA expression library from unfed female tick Haemaphysalis longicornis for screening and cloning potential antigenic genes.Methods Total RNA was isolated from unfed female ticks,mRNA was purified and a library of oligo(dT)-primed cDNA with added directional EcoR Ⅰ/Hind Ⅲ linkers was constructed from the purified mRNA.The constructed cDNA was ligated to the EcoRⅠ/HindⅢ arms of the ?SCREEN vector.Pure phage stocks were harvested by plaque purification and converted to plasmid subclones by plating phage on host strain BM25.8.Recombinant plasmids that were subcloned to E.coli BM25.8 were isolated and transformed into E.coli JM109.Recombinant plasmids abstracted from JM109 were identified by PCR and sequencing.Rusults The recombinant phage DNA was packaged by using phage-marker packaging extracts,resulting in a primary cDNA library with a size of 1.8?106 pfu.Data showed 100% of the library were recombinant and the titer of the amplified library was 2.4?109 pfu/ml.Forty-two clones of encoding immunodominant antigens were obtained from the cDNA library.Sequence analysis revealed 12 unique cDNA sequences and the encoded putative proteins showed similarities to H.longicornis tropomyosin mRNA,Rhipicephalus annulatus unknown larval protein mRNA,chromosome 2R of Drosophila melanogaster,mitochondrial DNA of H.flava,clones HqL09 unkown mRNA and Hq05 mRNA of H.qinghaiensis,and myosin alkali light chain protein mRNA.Conclusion The cDNA expression library from unfed female H.longicornis was successfully constructed and screening of protective genes may provide candidate antigens of the tick.