Cloning and sequencing of a carp β_s-crystallin cDNA

The mRNAs were extracted from common carp (Cyprinus carpio) lenses, purified, reverse transcribed, dC tailed and cloned into Escherichia coli with pBR322 as vector. The cloning efficiency was around 1·107 colonies per μg of mRNA. A clone (pC20) was found by hybrid-arrested translation to contain the cDNA related to carp crystallins. However, comparison of the derived amino-acid sequence with bovine γ-II and βs-crystallins indicates that this carp crystallin sequence resembles closely the bovine βs-crystallin and should be better classified as such except that this fish sequence does not contain the N-terminal 'arm' of four amino-acid residues present in bovine βs-crystallin.