Abstract
Purpose :
Oriculoauricular syndrome (OMIM 612109) is an autosomal recessive disease caused by mutations in the homeobox gene HMX1. It is characterized by defects in multiple ocular tissues, including the cataract in the lens and dystrophy in the retina, and distinct malformation of the outer ear, the details of the ocular defects and underlying mechanism are unknown. Our purpose was to generate a mouse model of the disease, which can be used to study and to better understand this disease.
Methods :
By homologous gene targeting, two Hmx1 alleles, Hmx1-lacZ and Hmx1-flox were generated. Hmx1-lacZ is used to analyze the expression of Hmx1 in different stages. Hmx1-flox is used to specifically delete Hmx1 in the retina and lens, two tissues affected in the disease. Immunofluorescence labeling, histology, lacZ staining and RNA-seq expression profiling are used to study the defects of the disease and the underlying mechanisms.
Results :
Using in situ hybridization and lacZ staining, we have uncovered that Hmx1 is expressed in the retina and lens through development with distinct patterns. By crossing Hmx1-flox with the retina-specific Six-cre line, we have successfully deleted Hmx1 in the retina. Preliminary analysis indicates that retina-specific deletion of Hxm1 leads to thinning of the inner nuclear layer, and subsequent degeneration of the photoreceptors. Further analysis of the defects is underway.
Conclusions :
We have generated a mouse model harboring a mutated Hmx1 allele, in which Hmx1 can be specifically and efficiently deleted both in the retina and lens. These mice thus be used to investigate the mechanisms of retinal degeneration and lens cataract formation manifested in the oriculoauricular syndrome.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.