DEVELOPMENTAL AND DIFFERENTIAL REGULATIONS IN GENE-EXPRESSION OF XENOPUS PLEIOTROPIC FACTOR-ALPHA AND FACTOR-BETA

Using conserved nucleotide sequences in mammalian osteoblast specific factor-1 (OSF-1) coding regions, we isolated two kinds of cDNA clones from the Xenopus brain library. The encoded proteins, named Xenopus pl eiotrophic factors (X-PTFs)-alpha and -beta, were 65 and 87% homologou s to human midkine and OSF-1, respectively. In the adult frog, X-ptf-a lpha was expressed in the ovary, brain, eye, bone, heart and lung, whe reas X-ptf-beta was expressed in the brain, eye and bone. By in situ h ybridization of the tailbud embryo, X-ptf-alpha mRNA was detected rath er broadly in the head/tail regions including the central nervous syst em (CNS), whereas X-ptf-beta mRNA was restricted to the CNS, particula rly in the hind-brain. During embryogenesis, X-ptf-alpha mRNA was dete cted in the one-cell stage embryo, whereas only zygotic expression was observed in X-ptf-beta. X-ptf-beta mRNAs contained similar to 79 bp t andem repeats in the 3'-untranslated region, complementary to those fo und in retinoic acid cellular receptor mRNA and in the sense strand of short interspersed repeat transcripts in X. laevis. (C) 1995 Academic Press, Inc.