Characterization and expression profile of complete functional domain of granulysin/NK-lysin homologue (buffalo-lysin) gene of water buffalo (Bubalus bubalis).

ABSTRACT

Granulysin (GNLY)/NK-lysin (NKL) is an effector antimicrobial cationic peptide expressed in the cytotoxic and natural killer lymphocytes. We report here cDNA sequence (405bp) encoding the complete functional domain of buffalo-lysin (bu-lysin), and its expression profile in the various tissues. The nucleotide sequence of bu-lysin exhibited >85% identity with the bovine lysin. Comparison of the deduced amino acid sequence of bu-lysin with those of GNLY/NKL of different species revealed the conservation of six cysteine (Cys) residues and five alpha helices. Unlike the homologues in other species, bu-lysin composed of 11 positively charged Lys residues as in equine. The expression of bu-lysin mRNA in the in vitro cultured lymphocytes was inducible and increased markedly (p<0.05) in a dose dependant manner when incubated with Concanavalin A (ConA). The expression of bu-lysin mRNA in the different tissues was variable comparatively higher in the spleen and lymph node, moderate in the uterine endometrium and low in the liver and kidney. These results indicate the existence and active expression of GNLY/NKL homologue in water buffalo having a significant influence in immune response.