Article

A conserved retinoic acid response element required for early expression of the homeobox gene Hoxb-1.

Laboratory of Developmental Neurobiology, National Institute for Medical Research, London, UK.
Nature (impact factor: 36.28). 09/1994; 370(6490):567-71. DOI:10.1038/370567a0 pp.567-71
Source: PubMed

ABSTRACT Within the Hoxb homeobox gene complex, Hoxb-1 is the earliest member expressed in the mesoderm and neuroectoderm of primitive streak and presomite embryos, preceding rhombomere-restricted expression in the hindbrain. Ectopic exposure of embryos to retinoic acid alters spatial aspects of Hox gene expression patterns. However, the role of retinoids in regulating these genes during normal development is unclear. We have now identified two enhancers, 3' of the mouse Hoxb-1 gene, which together reconstruct the early endogenous expression pattern and mediate the early ectopic response to retinoic acid. Furthermore, these regions are functionally conserved in both chicken and pufferfish (Fugu rubripes) Hoxb-1 genes. The enhancer that controls the retinoic acid response, and regulates expression predominantly in neuroectoderm, contains a retinoic acid response element (RARE). Point mutations in the RARE abolish expression in neuroectoderm. Therefore, this RARE is not only involved in the ectopic response to retinoic acid, but is also essential for establishing aspects of the early Hoxb-1 expression pattern.

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Keywords

earliest member
 
Ectopic exposure
 
ectopic response
 
endogenous expression pattern
 
genes
 
Hox gene expression patterns
 
Hoxb homeobox gene complex
 
Hoxb-1
 
Hoxb-1 expression pattern
 
mouse Hoxb-1 gene
 
normal development
 
Point mutations
 
presomite embryos
 
primitive streak
 
regions
 
retinoic acid
 
retinoic acid alters spatial aspects
 
retinoic acid response
 
retinoic acid response element
 
rhombomere-restricted expression