Abstract
Purpose: :
Although ß and γ–Crystallins had been considered for a long time to be present only in the ocular lens and structural protein to maintain the transparency of lens, extralenticular expression in normal and pathological state was indicated recently. However, nonrefractive function of these crystallins was totally unknown. In this study, we investigated the potential role of the ßB2, ßA1/A3 and γC –Crystallin.
Methods: :
Crystallins expressed in non–lens tissues were examined by immunoblotting analysis of proteins extracted from lens, cerebrum, cerebellum, retina, optic nerve, spinal cord, peripheral nerve, heart, aorta, lung, kidney, spleen, bowel, skeletal muscle, and testis of adult C57BL/6J mouse. Immunohistochemical study was performed by using cryosections of various tissues mentioned above. Cellular localization ofßB2, ßA1/A3 and γC–Crystallin was investigated in migrating lens epithelial cells isolated from porcine lens.
Results: :
ßB2 and ßA1/A3–Crystallins were expressed in lens, cerebrum, cerebellum, retina, heart, aorta, lung, kidney, and skeletal muscle. On the other hand, γC– Crystallin was observed in all tissue. Immunohistochemical study showed that ßB2, ßA1/A3 and γC –Crystallin were localized in M–line and I–band in skeletal muscle. ßB2 and γC –Crystallin were expressed in spermatocytes in testis. In addition, these crystallins were strongly expressed in the leading edges of cultured lens epithelial cells and co–localized with cytoskeletal protein actin.
Conclusions: :
ßB2, ßA1/A3 and γC –Crystallins were abundantly expressed in non–lens tissues and co–localized with actin in the leading edge of migrating lens epithelial cells. Our studies suggested ß and γ–Crystallins were related with changing of cell shape and cytoskeletal organization.
Keywords: crystalline lens • cytoskeleton • chaperones