DIFFERENTIAL DISPLAY ANALYSIS OF GENE-EXPRESSION IN DEVELOPING EMBRYOS OF XENOPUS-LAEVIS

Differential display (DD), an arbitrarily primed RT-PCR fingerprinting technique, is a novel approach for the search of differentially expre ssed transcripts. Using our improved DD protocol, reproducible cDNA fi ngerprints were successfully obtained from RNAs of Xenopus laevis embr yos at six representative stages. Parallel comparison among the finger prints revealed a number of bands with differential expression pattern s. Analysis with clones of three randomly chosen bands confirmed that their expression patterns were faithfully reflected on fingerprints, t hereby proving the reliability and validity of the approach. Nucleotid e sequencing of these clones revealed that one is identical with a kno wn transcript (cardiac actin), the second is a novel developmentally r egulated gene showing no significant homology with those reported prev iously, and the last is a close but unique relative of XK endo B gene showing somewhat different spatial expression pattern. These results i ndicated that the DD analysis provides a rapid and reliable way for th e identification of novel differentially expressed genes as well as a unique 'scope' for the survey of the changes in overall gene expressio n profiles occurring in the early embryonic development of Xenopus as well as of other organisms.