The homeobox-containing Engrailed (En-1) product down-regulates the expression of Pax-6 through a DNA binding-independent mechanism.
By in situ hybridization of quail neuroretinas, we observed that Engrailed (En-1) is expressed both in the ganglionic and the amacrine cell layers, similarly to Pax-6. Because we observed a decrease of Pax-6 expression in the neuroretina of hatched animals, we studied the effect of the chicken En-1 and En-2 proteins on Pax-6 expression. En-1 and to some extent En-2 were able to repress the basal and the p46Pax-6-activated transcription from the two Pax-6 promoters. Infection of retinal pigmented epithelium by a virus encoding the En-1 protein repressed the endogenous Pax-6, and a similar effect was observed with a homeodomain-deleted En-1. In vitro interaction indicates that En proteins are able to interact with the p46Pax-6 through the paired domain. This interaction negatively regulates the DNA-binding properties of the p46Pax-6. These results suggest an interplay between En-1 and Pax-6 during the central nervous system development and indicate that En-1 may be a negative regulator of Pax-6.
Plaza
S
S
Centre National de la Recherche Scientifique EP560, Institut Pasteur, Lille, France.
Langlois
M C
MC
Turque
N
N
LeCornet
S
S
Bailly
M
M
Bègue
A
A
Quatannens
B
B
Dozier
C
C
Saule
S
S
D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D015153:Blotting, Western; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism* / Q000502:physiology; D015536:Down-Regulation; D005136:Eye Proteins; D018398:Homeodomain Proteins / Q000276:immunology / Q000502:physiology*; D017403:In Situ Hybridization; D009419:Nerve Tissue Proteins / Q000276:immunology / Q000502:physiology*; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D011401:Promoter Regions, Genetic / Q000502:physiology; D011784:Quail; D012097:Repressor Proteins; D012160:Retina / Q000196:embryology / Q000378:metabolism; D014157:Transcription Factors; D014162:Transfection; D000099266:Engrailed 2 Protein
D004247:DNA; D004268:DNA-Binding Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D014157:Transcription Factors; D000099266:Engrailed 2 Protein