A. Saltzman et al., CLONING AND CHARACTERIZATION OF HUMAN JAK-2 KINASE - HIGH MESSENGER-RNA EXPRESSION IN IMMUNE CELLS AND MUSCLE-TISSUE, Biochemical and biophysical research communications, 246(3), 1998, pp. 627-633
We report on the cloning and sequence analysis of the mRNA coding for
full-length human Janus kinase 2 (Jak2). The human form of Jak2 is 113
2 amino acids in length with a M-r of 131 KDa. It has 95% sequence sim
ilarity to pig and rat Jak2. The highest level of mRNA expression was
found in the spleen, peripheral blood leukocytes, and testis. Also a s
ignificantly high level of Jak2 mRNA was found in heart and skeletal m
uscle. Northern blot analysis showed three mRNA species in all tissues
tested, except heart and skeletal muscle, of 7.6, 5.9, and 4.8 Kb. In
skeletal muscle and heart, three mRNA species of 7.6, 4.8, and 3.9 Kb
were identified. The catalytic domain of the human Jak2 was expressed
and its specificity for phosphorylating peptide substrates derived fr
om the gp130, STAT, and Jak3 molecules was determined and compared to
that for human Jak1 and Jak3. (C) 1998 Academic Press.