Identification and cloning of a novel tetraspanin (TSP) homologue from Brugia malayi.

This is the first report of a tetraspanin (TSP)-like molecule in the lymphatic filarial parasites. Expressed sequence tag (EST) database search for TSP like molecules in the filarial genome resulted in three significant EST hits (two partial ESTs from Brugia malayi and one full length EST from Wuchereria bancrofti). The full length gene cloned from B. malayi showed significant similarity to Caenorhabditis elegans TSP and human TSP and hence the gene was named B. malayi TSP (BmTSP). Subsequent Genbank analysis with the predicted ORF of BmTSP showed additional homologous genes reported from Schistosoma mansoni and Taenia solium parasites. Structural analyses showed that BmTSP has four transmembrane domains and other conserved domains such as CCG and two other critical cysteine residues present within the large extracellular loop similar to other reported TSPs. In addition, putative post-translational modifications such as N-glycosylation, protein kinase c phosphorylation, casein kinase II phosphorylation and N-myristoylation sites have been found in BmTSP sequence. Further, PCR analyses showed that BmTSP is differentially transcribed, with highest level of expression being present in the adult stages followed by L3 and mf stages. This study thus describes a novel TSP cloned from B. malayi, its putative functions in cuticle biogenesis and role in protective immunity.