PAX-QNR PAX-6, A PAIRED-BOX-CONTAINING AND HOMEOBOX-CONTAINING GENE EXPRESSED IN NEURONS, IS ALSO EXPRESSED IN PANCREATIC ENDOCRINE-CELLS/

After differential screening of a cDNA library constructed from quail neuroretina cells infected with the v-myc containing avian retrovirus MC29, we have isolated a cDNA clone Pax-QNR, homologous to the murine Pax6 which is mutated in the autosomal dominant mutation small eye (Se y) of the mouse and aniridia in man. Here we report the characterizati on of Pax-QNRIPax-6 expression in the chicken, quail, and mouse pancre as. In situ hybridization performed with E3 chick embryos demonstrated that, in addition to the documented expression of Pax-QNR/Pax-6 in th e neural tube, this gene is also expressed in the pancreatic bud. This expression is later restricted to discrete parts of the organ. From b acterially expressed Pax QNR peptides we obtained rabbit antisera (pai red domain, serum 11; domain between paired and homeo, serum 12; homeo domain, serum 13; and carboxyl-terminal part, serum 14) capable of spe cifically recognizing Pax-QNR/Pax-6 proteins (48, 46 kilodaltons) in c ell lines derived from alpha- and beta-pancreatic cells, but not from exocrine derived cell lines. We conclude that Pax-QNR/Pax-6 represents another gene expressed both in the endocrine pancreas and neuro-ectod ermic tissues.