Retinoic acid response elements as positive and negative regulators of the expression of the homeobox b-1 gene.
Retinoic acid-dependent homeobox Hoxb-1 gene expression offers an unanticipated example of both a positive and a negative transcriptional activity of RA, as exerted at different times during embryogenesis. A paradigm for the transduction of positive and negative signaling is the discovery that retinoic acid response elements (RAREs), positioned in the 3' enhancer and 5' promoter of the Hoxb-1 gene, may function respectively as positive and negative regulators, thereby permitting a diffused (early positive) as well as segmentally specified and limited (late negative) expression of the gene. This molecular action of retinoic acid may provide a mechanism for our understanding of normal embryogenesis and of the interference with this process by ectopic retinoic acid, thereby leading to teratogenesis.
De Luca
L M
LM
Differentiation Control Section, National Cancer Institute, Bethesda, MD 20892-4255, USA.
Ross
S A
SA
D000014:Abnormalities, Drug-Induced; D000818:Animals; D005786:Gene Expression Regulation / Q000187:drug effects*; D005801:Genes, Homeobox / Q000235:genetics*; D006801:Humans; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid; D014212:Tretinoin / Q000009:adverse effects / Q000494:pharmacology*
D014212:Tretinoin