Abstract
Purpose: :
Growth factor signaling pathways regulate many cellular processes including lens epithelial cell proliferation, and their differentiation into fiber cells. Recent studies from our laboratory have identified important roles for Sef and Sprouty (Spry), as negative regulators of this growth factor signaling in the lens. Interestingly, lenses deficient for these antagonists develop relatively normally; however, in lenses deficient for Spry, cataracts appear postnatally. To identify whether other negative regulatory genes may compensate for the absence of Sef and/or Spry, we set out to initially characterise the spatial and temporal expression in the lens of Spreds; sprouty-related proteins associated with inhibition of cell signaling pathways.
Methods: :
A range of detection and labeling techniques were used to determine the expression patterns of Spred 1, 2 and 3 during lens morphogenesis and postnatal lens growth.
Results: :
Spreds were identified in the lens, with strongest expression detected for Spred1, compared to Spred2 and Spred3. Interestingly, in most cases, the Spreds were most strongly expressed in the lens epithelium. All three of the Spreds were also strongly detected in other regions of the eye.
Conclusions: :
The identification of Spreds, another family of growth factor antagonists, in the eye and lens, establishes another putative level of regulation of growth factor signaling in these tissues. Further in vivo approaches using transgenic mice, either overexpressing or deficient for these molecules specifically in the lens, will provide insights into their specific role in lens morphogenesis, growth and pathology.
Keywords: signal transduction • growth factors/growth factor receptors • differentiation