Developmental expression of Pim kinases suggests functions also outside ofthe hematopoietic system

We have cloned a novel quail cDNA with strong homology to the pint family o f proto-oncogenes. The deduced amino acid (aa) sequence of the cDNA, named qpim, is more closely related to Xenopus Pim and to the recently identified rat Pim-3 than to human or rodent Pim-1 or Pim-2. The protein encoded by t he qpim cDNA can autophosphorylate itself and share substrates with murine Pim-l, suggesting functional redundancy to other Pim family serine/threonin e kinases. We have compared the expression of qpim in avian embryos to mous e pim-1, -2 and -3 by in situ hybridization. qpim shows a highly dynamic ex pression pattern, particularly at early developmental stages. Surprisingly, its expression pattern is not identical to any of the murine pint genes, w hich show complementary and/or partially overlapping expression sites both in- and outside of the hematopoietic system. Altogether, our results sugges t novel functions for Pim family kinases during embryonic development, in p articular in epithelia and in the central nervous system.