EXPRESSION OF A NA,K-ATPASE BETA3 SUBUNIT DURING DEVELOPMENT OF THE ZEBRAFISH CENTRAL-NERVOUS-SYSTEM

Zebrafish beta3, a full length cDNA clone encoding a zebrafish Na,K-AT Pase beta subunit, was isolated, The protein shares highest homology w ith the beta3 subunits of amphibians and mammals, slightly less homolo gy with the beta2 subunits, and is distinct from the beta1 subunits, T he fish beta subunit coassembled with alpha subunits to form Na,K-ATPa se enzymes when expressed in Xenopus oocytes, Embryonic expression was first detected by whole-mount in situ hybridization between 8-12 hr p ost-fertilization (hpf) in the head mesoderm, Subsequently, and up to 24 hpf, the mRNA was confined to four dorsal domains in the anterior n eural tube, After a transient downregulation during the second day, ex pression was again conspicuous in the nervous system of 3-day-old larv ae, Based on its distribution pattern, the fish beta subunit could be involved in setting up regional identities ire the developing fish CNS and in the differentiation of distinct cell types. (C) 1996 Wiley-Lis s, Inc.