Isolation and characterization of initiation fragments from lens 10S and 14S α-crystallin messenger ribonucleic acids

Abstract

The .alpha.-crystallin 10S and 14S mRNA for the B and A chains, respectively, were isolated from calf lenses. Initiation complexes were formed with both mRNA after which the unprotected regions were digested with ribonuclease T1. A single fragment of approximately 45 nucleotides was obtained from the 10S and 14S mRNA. The fragments retained the ability to reform initiation complexes under standard conditions. Two-dimensional fractionation of ribonuclease T1 digests indicated considerable similarity between the 10S and 14S fragments. Marked differences in the (U)G region were observed. The addition of the methylating agent S-adenosyl-L-methionine to the mRNA initiation system increased complex formation from 2-5 times, suggesting that methylation may be required for initiation.