Abstract
All immunoglobulins and T-cell receptors throughout phylogeny share regions of highly conserved amino acid sequence. To identify possible primitive immunoglobulins and immunoglobulin-like molecules, we utilized 3' RACE (rapid amplification of cDNA ends) and a highly conserved constant region consensus amino acid sequence to isolate a new immunoglobulin class from the sandbar shark Carcharhinus plumbeus. The immunoglobulin, termed IgW, in its secreted form consists of 782 amino acids and is expressed in both the thymus and the spleen. The molecule overall most closely resembles mu chains of the skate and human and a new putative antigen binding molecule isolated from the nurse shark (NAR). The full-length IgW chain has a variable region resembling human and shark heavy-chain (VH) sequences and a novel joining segment containing the WGXGT motif characteristic of H chains. However, unlike any other H-chain-type molecule, it contains six constant (C) domains. The first C domain contains the cysteine residue characteristic of C mu1 that would allow dimerization with a light (L) chain. The fourth and sixth domains also contain comparable cysteines that would enable dimerization with other H chains or homodimerization. Comparison of the sequences of IgW V and C domains shows homology greater than that found in comparisons among VH and C mu or VL, or CL thereby suggesting that IgW may retain features of the primordial immunoglobulin in evolution.
Full text
PDF




Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Altschul S. F., Gish W., Miller W., Myers E. W., Lipman D. J. Basic local alignment search tool. J Mol Biol. 1990 Oct 5;215(3):403–410. doi: 10.1016/S0022-2836(05)80360-2. [DOI] [PubMed] [Google Scholar]
- Bernstein R. M., Schluter S. F., Lake D. F., Marchalonis J. J. Evolutionary conservation and molecular cloning of the recombinase activating gene 1. Biochem Biophys Res Commun. 1994 Nov 30;205(1):687–692. doi: 10.1006/bbrc.1994.2720. [DOI] [PubMed] [Google Scholar]
- Chothia C., Boswell D. R., Lesk A. M. The outline structure of the T-cell alpha beta receptor. EMBO J. 1988 Dec 1;7(12):3745–3755. doi: 10.1002/j.1460-2075.1988.tb03258.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Davies J., Riechmann L. 'Camelising' human antibody fragments: NMR studies on VH domains. FEBS Lett. 1994 Feb 21;339(3):285–290. doi: 10.1016/0014-5793(94)80432-x. [DOI] [PubMed] [Google Scholar]
- Gish W., States D. J. Identification of protein coding regions by database similarity search. Nat Genet. 1993 Mar;3(3):266–272. doi: 10.1038/ng0393-266. [DOI] [PubMed] [Google Scholar]
- Greenberg A. S., Avila D., Hughes M., Hughes A., McKinney E. C., Flajnik M. F. A new antigen receptor gene family that undergoes rearrangement and extensive somatic diversification in sharks. Nature. 1995 Mar 9;374(6518):168–173. doi: 10.1038/374168a0. [DOI] [PubMed] [Google Scholar]
- Hill R. L., Delaney R., Fellows R. E., Lebovitz H. E. The evolutionary origins of the immunoglobulins. Proc Natl Acad Sci U S A. 1966 Dec;56(6):1762–1769. doi: 10.1073/pnas.56.6.1762. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hohman V. S., Schluter S. F., Marchalonis J. J. Complete sequence of a cDNA clone specifying sandbar shark immunoglobulin light chain: gene organization and implications for the evolution of light chains. Proc Natl Acad Sci U S A. 1992 Jan 1;89(1):276–280. doi: 10.1073/pnas.89.1.276. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hohman V. S., Schluter S. F., Marchalonis J. J. Diversity of Ig light chain clusters in the sandbar shark (Carcharhinus plumbeus). J Immunol. 1995 Oct 15;155(8):3922–3928. [PubMed] [Google Scholar]
- Kobayashi K., Tomonaga S., Tanaka S. Identification of a second immunoglobulin in the most primitive shark, the frill shark, Chlamydoselachus anguineus. Dev Comp Immunol. 1992 Jul-Aug;16(4):295–299. doi: 10.1016/0145-305x(92)90004-v. [DOI] [PubMed] [Google Scholar]
- Maizels N. Somatic hypermutation: how many mechanisms diversify V region sequences? Cell. 1995 Oct 6;83(1):9–12. doi: 10.1016/0092-8674(95)90227-9. [DOI] [PubMed] [Google Scholar]
- Mäkelä O., Litman G. W. Lack of heterogeneity in antihapten antibodies of a phylogenetically primitive shark. Nature. 1980 Oct 16;287(5783):639–640. doi: 10.1038/287639a0. [DOI] [PubMed] [Google Scholar]
- Rast J. P., Litman G. W. T-cell receptor gene homologs are present in the most primitive jawed vertebrates. Proc Natl Acad Sci U S A. 1994 Sep 27;91(20):9248–9252. doi: 10.1073/pnas.91.20.9248. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Saitou N., Nei M. The neighbor-joining method: a new method for reconstructing phylogenetic trees. Mol Biol Evol. 1987 Jul;4(4):406–425. doi: 10.1093/oxfordjournals.molbev.a040454. [DOI] [PubMed] [Google Scholar]
- Schluter S. F., Hohman V. S., Edmundson A. B., Marchalonis J. J. Evolution of immunoglobulin light chains: cDNA clones specifying sandbar shark constant regions. Proc Natl Acad Sci U S A. 1989 Dec;86(24):9961–9965. doi: 10.1073/pnas.86.24.9961. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thompson J. D., Higgins D. G., Gibson T. J. CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucleic Acids Res. 1994 Nov 11;22(22):4673–4680. doi: 10.1093/nar/22.22.4673. [DOI] [PMC free article] [PubMed] [Google Scholar]