Crystallins of the octopus lens. Recruitment from detoxification enzymes

• Published in: The Journal of biological chemistry Vol. 266; no. 35; pp. 24226 - 24231
• Main Authors: TOMAREV, S. I, ZINOVIEVA, R. D, PIATIGORSKY, J
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 15-12-1991
• Subjects: Aldehyde Dehydrogenase - genetics; Amino Acid Sequence; amino acids; Animals; Base Sequence; biochemical analysis; biochemical composition; Biological and medical sciences; Biological Evolution; Blotting, Northern; cDNA; Cell physiology; Cloning, Molecular; Crystallins - genetics; Crystallins - isolation & purification; Decapodiformes - genetics; DNA - genetics; DNA - isolation & purification; Fundamental and applied biological sciences. Psychology; Gene Library; genes; Glutathione Transferase - genetics; Glutathione Transferase - metabolism; Humans; Isoenzymes - genetics; Lens, Crystalline - physiology; Liver - enzymology; Marine; Molecular and cellular biology; Molecular Sequence Data; Multigene Family; Octopodiformes - genetics; Octopus dofleini; Oligodeoxyribonucleotides; proteins; RNA - genetics; RNA - isolation & purification; Sequence Homology, Nucleic Acid; Vision, photoreception; Northern blotting; Eye; Crystallin; Enzyme; Glutathione transferase; Primary structure; Invertebrata; Aldehyde dehydrogenase
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)54416-1

The eye lens crystallins of the octopus Octopus dofleini were identified by sequencing abundant proteins and cDNAs. As in
squid, the octopus crystallins have subunit molecular masses of 25-30 kDa, are related to mammalian glutathione S-transferases
(GST), and are encoded in at least six genes. The coding regions and deduced amino acid sequences of four octopus lens cDNAs
are 75-80% identical, while their non-coding regions are entirely different. Deduced amino acid sequences show 52-57% similarity
with squid GST-like crystallins, but only 20-25% similarity with mammalian GST. These data suggest that the octopus and squid
lens GST-like crystallin gene families expanded after divergence of these species. Northern blot hybridization indicated that
the four octopus GST-like crystallin genes examined are lens-specific. Lens extracts showed about 40 times less GST activity
using 1-chloro-2,4-dinitrobenzene as substrate than liver extracts of the octopus, indicating that the major GST-like crystallins
are specialized for a lens structural role. A prominent 59-kDa crystallin polypeptide, previously observed in octopus but
not squid and called omega-crystallin (Chiou, S.-H. (1988) FEBS Lett. 241, 261-264), has been identified as an aldehyde dehydrogenase.
Since cytoplasmic aldehyde dehydrogenase is a major protein in elephant shrew lenses (eta-crystallin; Wistow, G., and Kim,
H. (1991) J. Mol. Evol. 32, 262-269) the octopus aldehyde dehydrogenase crystallin provides the first example of a similar
enzyme-crystallin in vertebrates and invertebrates. The use of detoxification stress proteins (GST and aldehyde dehydrogenase)
as cephalopod crystallins indicates a common strategy for recruitment of enzyme-crystallins during the convergent evolution
of vertebrate and invertebrate lenses. For historical reasons we propose that the octopus GST-like crystallins, like those
of the squid, are called S-crystallins.