Abstract
Abstract: :
Purpose:During development the lens becomes transparent by eliminating most of the cellular organelles from the fiber cell. This process is remarkably similar to apoptosis with, however, a different outcome. The anuclear lens fiber cells are not phagocytosed and persist throughout the life of the lens. Several proteins that are involved in regulation of apoptosis were shown to be differentially expressed in the lens. Here, we present data on the expression of a chicken homolog of a member of the tumor necrosis factor (TNF) super family, TRAIL, during embryonic lens development. We have also determined the effect of overexpression of cTRAIL protein on lens development. Methods:The full-length cDNA sequence of chicken TRAIL was obtained by a combination of several techniques, such as screening a cDNA library and 5' and 3' RACE. We analyzed the expression of chicken cTrail mRNA from stage 14 to stage 28 (E6) using in situ hybridization. We cloned a full-length protein under control of a subgenomic promoter of a double-subgenomic Sindbis virus replicon and packaged them into infectious viral particles. This replicon also expressed the GFP protein as a reporter. Viral particles were injected into the lens vesicle at stages 16-18. The efficiency of the infection was assessed by GFP expression. The infected lenses were compared with uninfected lenses from the same embryo using different imaging techniques. Results and Conclusions:We found that cTRAIL has a dynamic pattern of expression in the developing eye and is localized to the elongating fiber cell at later stages. The overexpression of cTRAIL in the lens leads to abnormal eye development with mild-to-severe malformation of the lens, depending on the level of expression. Since the apoptosis-like process is involved in terminal differentiation of the lens fibers, we hypothesize that TRAIL could be an important regulator of this process.
Keywords: apoptosis/cell death • cytokines/chemokines • cataract