MOLECULAR MASS-DISTRIBUTION OF WATER-SOLUBLE CRYSTALLINS FROM THE HUMAN FETAL LENS DURING DEVELOPMENT

The water-soluble crystallins of twenty human foetal lenses with gestational ages of 112-231 days were analysed by size-exclusion chromatography. The crystallin distribution showed similar patterns for all foetal lenses, but clear changes in the proportions of different crystallins were evident. The distribution showed that the water-soluble part of all the lenses already contained high-molecular-mass material. Also β-crystallins of high molecular mass (βH), formed by post-translational changes, were detected in all stages. During gestation, the percentage of high-molecular-mass crystallins and of α-crystallins of low molecular mass (αL) decreased significantly. The total β-crystallins (βT) and the total γ-crystallins (γT) increased significantly. The βH-crystallins (β1+2) decreased, whereas the βL-crystallins (β3) increased significantly. The low Mr crystallins were resolved into three peaks, designated βs-, γH- and γL-crystallins. They increased significantly during development. These significant increases of the low Mr crystallins took place exclusively in the developing lens. The rate of protein synthesis of the low Mr crystallins was 23% of the total water-soluble crystallin synthesis rate. © 1990.