REGIONAL EXPRESSION OF THE CWNT-4 GENE IN DEVELOPING CHICK CENTRAL-NERVOUS-SYSTEM IN RELATIONSHIP TO THE DIENCEPHALIC NEUROMERE D2 AND A DORSAL DOMAIN OF THE SPINAL-CORD

Members of the Wnt gene family code for cysteine-rich, secreted protei ns, which are differentially expressed in the developing brain and pos sibly act as an intercellular signaling molecule. A Wnt gene, e.g., Wn t-1 is known to be essential for specification of the midbrain cell fa te. Since other members of the Wnt genes are likely to be also involve d in development of the brain, we searched chick Wnt members expressin g in specific domains of the brain. We found several novel Wnt members expressing specifically in the central nervous system of chick embryo s. One of the genes was intensely expressed in a segment of the at sta ges 14 and 20 and in a dorsal region of the spinal cord at stage 20. A lthough the expression patterns differ from those of mouse or Xenopus Wnt-4, the gene is highly homologous to the mouse or frog Wnt-4. Thus, we designated the gene as Cwnt-4 (chick Wnt-4). Our results suggested that Cwnt-4 is involved in segmentation of the forebrain into the neu romere D2 and in differentiation of the dorsal region of the spinal co rd. (C) 1994 Academic Press, Inc.