CLONING OF THE GENE ENCODING RAT JAK2, A PROTEIN-TYROSINE KINASE

A complete cDNA clone encoding the rat JAK2 protein tyrosine kinase wa s isolated from an Nb2-SP (rat pre-T lymphoma cell line) cDNA library. The nucleotide (nt) and deduced amino acid (aa) sequences for this cl one were determined and an open reading frame of 3399 bp, encoding a p rotein of a deduced mass of 130 kDa, was found. The coding regions of the rat and murine JakZ clones share 93.4% nt identity and 97.1% aa id entity, Northern analysis demonstrated that the 5-kb mRNA is highly ab undant in brain and spleen, less abundant in skeletal muscle and testi s, and detectable in kidney, heart, lung and liver. Translation of the rat Jak2 mRNA in rabbit reticulocytes results in a protein which is s pecifically immunoprecipitated by antibodies (Ab) recognizing JAK2, bu t not by Ab recognizing JAK1.