Pax-6 expression and activity are induced in the reepithelializing cornea and control activity of the transcriptional promoter for matrix metalloproteinase gelatinase B.
Recent evidence supports the idea that matrix metalloproteinases (MMPs) act as morphogenetic regulators in embryonic and adult events of tissue remodeling. MMP activity is controlled primarily at the level of gene expression. In a recent study we characterized the transcriptional promoter of the MMP gene, gelatinase B (gelB), in transgenic mice, demonstrating the requirement for DNA sequences between -522 and +19 for appropriate activity. In this study we investigated factors required for gelB promoter activity in the developing eye and reepithelializing adult cornea. Pax-6 is a homeobox and paired domain transcription factor that acts at the top of the hierarchy of genes controlling eye development. Pax-6 is also expressed in the adult eye. We show here that the tissue expression pattern of Pax-6 overlaps extensively with gelB promoter activity in the developing and adult eye. In addition Pax-6 is observed to be upregulated in repairing corneal epithelium, as is gelB promoter activity. In cell culture transfection experiments, we identified two promoter regions which mediate positive response to Pax-6. By electrophoretic mobility shift assay, we further pinpoint two Pax-6 binding sites within these response regions and demonstrate direct interaction of the Pax-6 paired domain with one of these sites. These data suggest a mechanism by which Pax-6 may direct gelB expression in an eye-specific manner.
Sivak
J M
JM
Vision Research Laboratories of the New England Eye Center, Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
Mohan
R
R
Rinehart
W B
WB
Xu
P X
PX
Maas
R L
RL
Fini
M E
ME
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003315:Cornea / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D004247:DNA / Q000378:metabolism; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics*; D004847:Epithelial Cells / Q000166:cytology; D005136:Eye Proteins; D018398:Homeodomain Proteins; D020780:Matrix Metalloproteinase 9 / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D014158:Transcription, Genetic
D017931:DNA Primers; D004268:DNA-Binding Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D012097:Repressor Proteins; D004247:DNA; D020780:Matrix Metalloproteinase 9