Variations Of 45W, 14ku And 18ku Genes From Major Species Of Taeniidae

Complementary DNAs (cDNAs) of 45W gene, 14ku-and 18ku genes were amplified from total RNA of Taenia solium and other cestodes using reverse transcription polymerase chain reaction (RT-PCR). The agarose gel electrophoresis of the PCR products showed that the target DNA fragments were specifically amplified, respectively. The fragments were purified using DNA purification kit, inserted into pGEM-T Easy or pMD18-T Vector, and transformed into E coli JM 109 and then sequenced. Our data were aligned with the related sequences from GenBank and aligned using DNAstar software.The results show that eight A-type, nine IB-type and one Otype transcripts' cDNAs of Taenia solium oncosphere have been obtained with a 795bp, 459bp and 168bp open reading frame, respectively. These transcripts belong to the T. solium 45W gene family with a nucleotide divergence of 0.4%-20. 6% and with a amino acid divergence of 1. 0%-45.2%. Nearly all transcripts are the new members reported at the first time, while two almost have the same sequences as TS045W-4B reported in GenBank. 45W proteins' pI varies from 4.5 to 9.2.The most commonly used amino acids are Leu, Thr, Ser, Val and Ala in T. solium 45W proteins (some 50% off all amino acids), While the rarest is Cys. Positional biases in codon positions are shown in TS045W. A is favoured in the first and third positions, and T is favoured in the second postion. Amino acids for which all four bases can exist in the third position show a tendency to favour particular codons. Few of the memembers in the 45W gene family have difference in codon usage.The cDNAs of 14ku- and 18ku genes have been obtained from T. solium, Echinococcus granulosus and T. hydatigena. The 14ku- and 18ku genes are related and comprise a gene family with a 258bp and 261 bp open reading frame and with 0-1 and 2-3 potential N-linked glycosylation sites, respectively, which is reported at the first time. The 14ku cDNAs from T. Hydatigena and T. sioiumoncospheres, 18ku cDNAs from E. granulosus and T. sioium oncospheres are reported at the first time. There are a nuceotide divergence of 13. 6%-28.0% between 14ku- and 18ku cDNAs.