CLONING AND EXPRESSION OF CDNA-ENCODING XENOPUS-LAEVIS BONE MORPHOGENETIC PROTEIN-1 DURING EARLY EMBRYONIC-DEVELOPMENT

The Xenopus laevis DNA fragment encoding a protein homologous with hum an bone morphogenetic protein-1 (BMP-1) was amplified by polymerase ch ain reaction (PCR) from cDNA derived from stage 26 (st.26) embryonic R NA. Subsequently this fragment was used as a probe to isolate cDNA clo nes by screening of a X. laevis st.24 embryonic cDNA library. Two part ial clones (22 and 63) were obtained and the missing 5'-end of the clo ne 22 was extended by the anchored PCR technique. The nucleotide seque nce of the resulting clone (22AN) contained an open reading frame codi ng for a protein with 707 deduced amino acids. Three sizes of mRNA (2. 9, 5.2 and 6.6 kb) were detected in blastula (st.9) and early gastrula (st.10) embryos, and in hatched tadpole (st.40), but little or no exp ression was observed in morula (st.7) and late gastrula (st.12) embryo s, suggesting a physiological role(s) of X. laevis BMP-1 in normal emb ryonic development.