Synthesis of Lens Protein in vitro: Formation of beta-Crystallin

Abstract

Upon addition of lens polyribosomes to a reticulocyte-cell-free system, α, βl, and γ crystallin are synthesized, while βh crystallin is not formed. This phenomenon is comparable to the bio-synthetic events in the lens-cell-free system and in tissue culture. It is shown that βh crystallin formation depends upon the presence of a polypeptide βB_1b which arises by posttranslational modification. The putative precursor for βB_1b is a polypeptide βB_1a of which the messenger with a sedimentation coefficient of 12.5 S has been isolated.