Gradient refrakčního indexu v oku čtyřhranky: analýza exprese specifických genů

Abstract

Lenses are spread through animal kingdom as an improvement of different eye types. Despite conservation of some key regulators and shared use of photopigment opsin, eyes and their lenses develop by variable mechanisms impeaching their monophyletic origin. Tripedalia cystophora (T. c), a cubozoan jellyfish, is an emerging new model for studying eye evolution. The presence of advanced lens-containing eyes (firstly incident within metazoans in this phylum of Cnidaria), the two types of lesser eyes, the use of pax gene and vertebrate type of phototransduction cascade for eye establishment make this jellyfish an useful tool for comparing eye development and different evolutionary strategies. We focused on the lenses of T.c. and studied formation of their refractive index gradient to reveal its mechanism. Using new antibodies raised against J1 and J2 crystallins (proteins of the T. c. lens), TEM and histology we found that graded refractive index is of protein origin and formed by unequal accumulation of proteins (particularly J1 and J2 crystallins) in different layers of the lens. We have shown that J1 crystallin occurs also in the lesser eyes (ocelli) suggesting how the lens mass can evolved. The synthesis of J2 crystallin in lens development has been examined. Furthermore we have prepared J2 crystallin fused...