The Effects of Betab2-Crystallin Mutation on TGFBeta Signaling Leading to Epithelial-Mesenchymal Transition (EMT)

Fisher, Megan R.
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University of Delaware
The mammalian eye lens consists of fiber cells covered on the anterior surface by a monolayer of cuboidal epithelial cells. The most abundant protein in adult lens fibers is βB2-crystallin. It has recently been demonstrated that in mice homozygous for a 12 nucleotide deletion in the βB2-crystallin gene (Crybb2Phil), the lens epithelium undergoes an epithelial-mesenchymal transition (EMT) leading to severe lens abnormalities. The TGFβ signaling pathway is involved in other cases of EMT in the lens and other systems. Therefore, a SuperArray real time RT-PCR gene expression panel was used to test the hypothesis that TGFβ signaling is activated in the Crybb2Phil homozygous lens. It was found that of the 84 genes represented on the panel, 15 were significantly upregulated in the Crybb2Phil lens epithelium at 4 months of age. These results were used to select genes of interest for further investigation. The mRNA expression of several genes was studied at earlier points in development. This showed that expression of several of these genes changed over time in a manner indicating TGFβ activity between 3 weeks and 2 months of age.