Abstract
We have shown that gelsolin is one of the most prevalent water-soluble proteins in the transparent cornea of zebrafish. There are also significant amounts of actin. In contrast to actin, gelsolin is barely detectable in other eye tissues (iris, lens, and remaining eye) of the zebrafish. Gelsolin cDNA hybridized intensely in Northern blots to RNA from the cornea but not from the lens, brain, or headless body. The deduced zebrafish gelsolin is approximately 60% identical to mammalian cytosolic gelsolin and has the characteristic six segmental repeats as well as the binding sites for actin, calcium, and phosphatidylinositides. In situ hybridization tests showed that gelsolin mRNA is concentrated in the zebrafish corneal epithelium. The zebrafish corneal epithelium stains very weakly with rhodamine-phalloidin, indicating little F-actin in the cytoplasm. In contrast, the mouse corneal epithelium contains relatively little gelsolin and stains intensely with rhodamine-phalloidin, as does the zebrafish extraocular muscle. We propose, by analogy with the diverse crystallins of the eye lens and with the putative enzyme-crystallins (aldehyde dehydrogenase class 3 and other enzymes) of the mammalian cornea, that gelsolin and actin-gelsolin complexes act as water-soluble crystallins in the zebrafish cornea and contribute to its optical properties.
Highlights
The transparent and refractive properties of the eye lens depend upon the crystallins, which often differ among species in a taxon-specific fashion (6)
Corneal epithelial cells, like lens cells, contain unexpectedly high proportions of selected proteins (16 –19), raising the possibility that they may have structural roles related to transparency as do lens crystallins
The taxon-specific accumulation of intracellular water-soluble proteins, often enzymes, in the cornea resembles the high concentration of crystallins and enzyme-crystallins of the eye lens (6 – 8)
Summary
The transparent and refractive properties of the eye lens depend upon the crystallins, which often differ among species in a taxon-specific fashion (6). Corneal epithelial cells, like lens cells, contain unexpectedly high proportions of selected proteins (16 –19), raising the possibility that they may have structural roles related to transparency as do lens crystallins. These abundant intracellular corneal proteins are often enzymes, reminiscent of the enzyme-crystallins in the lens, suggesting that they are not serving strictly metabolic roles. By analogy with the lens crystallins and putative enzyme-crystallins of the cornea (28), the overexpression of gelsolin and the abundance of non-filamentous actin in the zebrafish cornea suggest a crystallin-like role for these cytoskeletal proteins related to vision and tissue transparency
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
