Abstract
Janus kinase2 (JAK2) is one of an important family that function primarily in signal transduction through contact with signal transducer and activator of transcription (STAT) proteins which reflects the high important role of JAK2 and its family. Chicken JAK2 protein is found to be formed of 1129 amino acids. The phosphorylation tyrosine residues were conserved between chicken, human and mouse. Expression analysis of chicken JAK2 showed a wide range of expression in all used tissues and cell lines. The expression was high in T-cell fraction when compared with that of B-cell one. The expression of chicken JAK2 showed a time course dependent of lipopolysaccharide (LPS) stimulation in spleen and bursa tissues and in IN24 cell line. The stimulation by LPS showed a high expression of chicken JAK2 in spleen and bursa by in-stiu hybridization studies.