Cloning and molecular characterization of microneme protein-3 (MIC3) gene of Izatnagar and Chennai isolates of Toxoplama gondii

Toxoplasma gondii is an obligate intracellular protozoan parasite with a broad host range involving both mammals and birds. Toxoplasma gondii infection is responsible for abortion, stillbirth and neonatal losses in all types of livestock, especially in sheep and goats. The fulllength gene of 1080 bp was PCR and RT-PCR amplified from genomic DNA and cDNA of Chennai and Izatnagar isolates of T. gondii, providing evidence for an intron-free gene structure. The coding region spanning the MIC3 gene of T. gondii has been ligated into a cloning vector P^{GEMT easy} and introduced in Escherichia coli. The positive clones were custom sequenced by Sanger's dideoxy method. Both isolate of Iztnagar and Chennai MIC3 genes were encoding the theoretical molecular mass of 38 kDa with deduced amino acids of 359. The MIC3 gene of Chennai isolate has 98.6 and 98.7% identity with China and ME49 strains, respectively and Izatnagar isolate has 97.9 and 98.1% identity with China and ME49 strains. Indian isolates have shown 98.1% similarity among them. Phylogenitically, Chennai isolate was close to China and ME49 strain compared to Izatnagar isolate. Further expression studies are warranted to know the diagnostic and prophylactic potentiality of MIC3 protein of local isolates.