Comparison of optic lens proteins among animals at different stages of development

The purpose of this investigation was to study and compare the electrophoretic patterns of optic lens proteins of different species of domestic animals at pre- and post-natal ages. Optic lenses were removed from the embryo or adult sheep, cattle, goat, camel and chicken at the slaughter-house then homogenized and subjected to sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). In all animals, except chicken, majority of proteins had molecular weights of less than 33 kDa and their concentrations were not affected by the age of animals at pre- or post-natal stages. A 9 kDa protein which was present in adult sheep optic lens was absent in sheep fetal lenses at different age groups. Prominent differences were observed in camel and chicken. In camel, proteins with molecular weights of 30 and 38 kDa were present, the concentration of which was much lower in other animals. A protein of 57 kDa which constituted the major protein of chicken optic lens was absent in other species of animals. The concentration of proteins in the range of 25-30 kDa increased with the age of chicken embryos. These proteins were remarkably different from those of adult chicken lens proteins except the 57 kDa protein which was also the predominant protein in the embryo. The 38 kDa protein disappeared and a 20 kDa protein appeared in the chicken embryo lens as compared with adult chicken lens. These data indicate extensive differences in the lens proteins of animals and suggest different physiological functions of lens proteins in different animals at different stages of development.