Identification of known and novel genes whose expression is regulated by endogenous retinoic acid during early...

Retinoic acid (RA) derived from vitamin A is necessary for, among other things, mammalian embryonic development. Although the impact of RA-dependent gene-regulation on embryonic development has been examined through genetic disruption of the retinoid receptors, the understanding of the underlying molecular mechanism remain unclear, in part, due to the difficulty in identifying RA-regulated genes in an intact embryo. We report here that RA-regulated genes can be identified from total RA-deficient embryos created by retinol-binding protein antisense (RBP-AS) oligodeoxynucleotide treatment in conjunction with differential display. Of the 28 genes isolated, 15 genes matched known genes in the GenBank database and the others either represented EST sequences or encoded novel genes. Semi-quantitative reverse transcriptase-polymerase chain reaction verified that the mRNA levels of mouse DN 38, COL VI 3 alpha, cul-1, alpha-tropomyosin, and PP2A-C alpha were substantially increased, whereas mouse Msh 2, Ndufa2, Ribosomal protein S19, sFRP-1, GDAP-10 and mSmcD were significantly decreased in vitamin A deficient (VAD) embryos compared to the control embryos. The utility of the method is exemplified by our finding that several genes in the Wnt signaling pathway are vitamin A regulated in day 9.0 post coitum (p.c.) embryos.