Intracorneal positioning of the lens in Pax6-GAL4/VP16 transgenic mice.
OBJECTIVE
The purpose of this study was to establish a GAL4/VP16-based binary transactivation system that was active in the lens and corneal epithelium of transgenic mice.


METHODS
We generated transgenic mice with the transcriptional transactivator GAL4/VP16 driven by a modified Pax6 promoter that is active in lens and corneal epithelial cells. We also generated and tested UAS-lacZ reporter mice. Wild type and transgenic mice were analyzed by histological, in situ, and Southern hybridization techniques.


RESULTS
Five families (OVE1931, OVE1934, OVE1935, OVE1936, and OVE1937) that carry the Pax6-GAL4/VP16 transgene were generated. Unexpectedly, mice from three of the transgenic lines showed ocular abnormalities. In the family OVE1936, cataracts were seen in the heterozygous mice at the time of eyelid opening and homozygotes showed microphthalmia. Transgenic mice in families OVE1931 and OVE1937 appeared normal. Histological analysis of ocular sections of OVE1934, OVE1935, and OVE1936 homozygous transgenic mice showed intracorneal positioning of the lens. The corneal stromal cells were disorganized and there was no distinctive corneal endothelial layer. In situ hybridizations showed robust expression of the GALVP16 transgene in the lens and corneal epithelial cells of the OVE1934, OVE1935, and OVE1936, but not in OVE1931 or OVE1937 families. Bigenic embryos generated by mating the Pax6-GAL4/VP16 mice to the UAS-lacZ mice showed that the GAL4/VP16 transgenic protein is functional and can induce eye-specific expression of a UAS-lacZ reporter gene.


CONCLUSIONS
Our data suggest that (1) expression the GAL4/VP16 transgene induces changes in gene expression in lens cells, (2) that developmentally important genes are affected, and (3) that bigenic phenotypes will need to be interpreted with caution.
Govindarajan
Venkatesh
V
Cancer Center, Creighton University, Omaha, NE 68178, USA. g.v@creighton.edu
Harrison
Wilbur R
WR
Xiao
Ningna
N
Liang
Dongcai
D
Overbeek
Paul A
PA
D000818:Animals; D015139:Blotting, Southern; D002386:Cataract / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D003315:Cornea / Q000002:abnormalities* / Q000378:metabolism / Q000473:pathology; D003316:Corneal Diseases / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005124:Eye Abnormalities / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D017403:In Situ Hybridization; D007908:Lens, Crystalline / Q000002:abnormalities* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008850:Microphthalmos / Q000235:genetics / Q000473:pathology; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation / Q000502:physiology*; D019076:Transgenes; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D005136:Eye Proteins; C070633:Gal-VP16; D018398:Homeodomain Proteins; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; C000605732:Pax6 protein, mouse; D012097:Repressor Proteins; D015534:Trans-Activators; D001616:beta-Galactosidase