Pax-QNR/Pax-6, a paired box- 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 (Sey) of the mouse and aniridia in man. Here we report the characterization of Pax-QNR/Pax-6 expression in the chicken, quail, and mouse pancreas. In situ hybridization performed with E3 chick embryos demonstrated that, in addition to the documented expression of Pax-QNR/Pax-6 in the neural tube, this gene is also expressed in the pancreatic bud. This expression is later restricted to discrete parts of the organ. From bacterially expressed Pax-QNR peptides we obtained rabbit antisera (paired domain, serum 11; domain between paired and homeo, serum 12; homeodomain, serum 13; and carboxyl-terminal part, serum 14) capable of specifically recognizing Pax-QNR/Pax-6 proteins (48, 46 kilodaltons) in cell 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-ectodermic tissues.