SEQUENCE OF THE HUMAN LENS BETA-B2-CRYSTALLIN-ENCODING CDNA

This study reports the nucleotide (nt) sequence of the human betaB2-crystallin (hbetaB2-Cry)-encoding cDNA (hbetaB2-cry). The hbetaB2-cry gene encodes a major structural protein in the lens of the vertebrate eye. Sequence information obtained from mouse genomic clones and the mouse betaB2-cry cDNA (mbetaB2-cry) sequence was used to design oligodeoxyribonucleotide primers, corresponding to exon 1, transcription start points, and termination and polyadenylation sites, that were used in the polymerase chain reaction (PCR) to generate full-length cDNA clones from total human lens RNA. In addition, cDNA libraries were made with lambdagt11 from both human fetal and adult lens tissue RNAs, and screened with a mbetaB2-cry cDNA clone. The full-length hbetaB2-cry cDNA is 721 bp and contains an open reading frame of 612 nt. It codes for a 23-kDa protein of 205 amino acid residues. Comparison of the overall nt and deduced aa sequences shows a greater similarity of hbetaB2-cry to bovine betaB2-cry than to mbetaB2-cry or rat betaB2-cry.