Classification of Rat Lens Crystallins and Identification of Proteins Encoded by Rat Lens mRNA

Abstract

Endogenous rat lens crystallins have been separated by gel filtration into four fractions, alpha, beta H, beta L and gamma-crystallin. Elution patterns of soluble lens proteins from animals of different ages show a relative decrease of beta H and gamma-crystallin during aging. Conversely the relative amounts of alpha and beta L-crystallin are enhanced. The rat crystallin subunits from the four fractions were characterized by one-dimensional and two-dimensional gel electrophoretic techniques. From the results a classification could be derived and a nomenclature for the soluble rat lens proteins is proposed. The products synthesized by rat lens mRNAs in a heterologous cell-free system have also been characterized. Co-electrophoresis of the radioactive products synthesized de novo together with the isolated unlabeled protein fractions on two-dimensional gels shows the relation between primary gene products and their posttranslationally modified derivatives.