Cloning and characterization of human Jak-2 kinase: high mRNA expression in immune cells and muscle tissue.
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 1132 amino acids in length with a M(r) of 131 KDa. It has 95% sequence similarity to pig and rat Jak2. The highest level of mRNA expression was found in the spleen, peripheral blood leukocytes, and testis. Also a significantly high level of Jak2 mRNA was found in heart and skeletal muscle. 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 from the gp130, STAT, and Jak3 molecules was determined and compared to that for human Jak1 and Jak3.
Saltzman
A
A
Gene Medicine Department, Rhône-Poulenc Rorer Central Research, Collegeville, Pennsylvania 19426, USA.
Stone
M
M
Franks
C
C
Searfoss
G
G
Munro
R
R
Jaye
M
M
Ivashchenko
Y
Y
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D015723:Gene Library; D006801:Humans; D053614:Janus Kinase 2; D007962:Leukocytes / Q000201:enzymology; D008297:Male; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D009842:Oligopeptides / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013154:Spleen / Q000201:enzymology; D013379:Substrate Specificity; D013737:Testis / Q000201:enzymology; D014018:Tissue Distribution
D018076:DNA, Complementary; D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507927:Jak2 protein, rat; D053614:Janus Kinase 2