In a search for nuclear hormone receptors expressed in early development we found that Xenopus laevis eggs contain mRNAs from two retinoic acid receptor genes (xRARα and xRARγ) and two retinoid "X" receptor genes (xRXRα and xRXRγ). We also show that RXRs are members of a family of at least three genes, thus expanding the number of genes encoding retinoic acid-responsive transcription factors to six. With the exception of xRXRγ, these maternal mRNAs are degraded before gastrulation. The RXRs isolated are differentially activated by retinoic acid and by 3,4-didehydroretinoic acid. Considered together, these four receptors provide a molecular basis for the pleiotropic effects of retinoic acid on early development, and their pattern of expression suggests a role for retinoic acid at the earliest stages of embryonic determination.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1992|