cloning, and molecular characterization of polymorphic iranian isolate theileria annulata surface protein (tasp)

background: because of the strong immunologic responses of surface protein tasp in theileria annu­lata infected host, we tried to characterize this protein in a t. annulata isolate from iran. methods: the rna prepared from t. annulata infected cells was used to produce smart-ds-cdna. the double strand cdna was then amplified with primers derived from tasp mrna se­quences. the pcr product was cloned in ptz57r/t vector, sequenced and registered under acces­sion no. jq003240 in genbank. results: the sequence analysis showed 90%-94% nucleotide sequence identity and 68%-94% amino acid homology to the corresponding sequences of tasp gene by t. annulata , t. sp . china i , t. sp . china and t. lestoquardi and three t. annulata reported from iran respectively. interestingly, the sequence analysis also showed small nucleotide sequence region near the 5` end in which the presented tasp protein differed very strongly from the other known tasp sequences. for the preparation of the recombi­nant protein, the cdna was cloned in pqe-32 vector, the recombinant protein was pre­pared and assayed by theileria infected bovine serum. conclusion: the polymorphism in tasp gene could be detected in intra- as well as inter species. the different characterized tasp proteins had a common identic region, which may be helpful for develop­ment of broad band vaccine based on the recombinant proteins. the polymorphism in this gene, make this protein also interesting for the diagnostic purposes.