Molecular basis for differing antineurogenic effects of GATA-1a and GATA-1b in Xenopus

The erythroid transcription factor GATA-1 in Xenopus has been cloned as a p air of presumably duplicated genes designated as xGATA-1a and xGATA-1b. Alt hough both xGATA-1a and xGATA-1b are able to stimulate erythropoiesis, only xGATA-1b is capable of inhibiting neurogenesis in Xenopus embryos. Chimera s of these two genes were constructed by permuting coding and untranslated regions (UTR) on both ends of these two xGATA-1, and their neurogenesis-inh ibitory effects were studied. These results reveal that (1) sequence variat ions between the coding regions alone do not account for the neurogenesis e ffect; (2) 3' UTR of xGATA-1a causes the loss of the neurogenesis inhibitio n of xGATA-1b; (3) 3' UTR of xGATA-1b is essential to inhibit neurogenesis. In addition, the presence of either UTR does not affect the stability of t he mRNA in vitro. These observations suggest the influence of 3' UTR in xGA TA-1 on the inhibition of neurogenesis. (C) 2000 Academic Press.