Genes encoding putative natural killer cell C-type lectin receptors in teleostean fishes

doi:10.1073/pnas.1235938100

Genes encoding putative natural killer cell C-type lectin receptors in teleostean fishes

Max-Planck-Institut für Biologie, Abteilung Immungenetik and Abteilung Membranbiochemie, Corrensstrasse 42, D-72076 Tübingen, Germany

Edited by Irving L. Weissman, Stanford University School of Medicine, Stanford, CA (received for review October 2, 2002)

Abstract

Mammalian natural killer (NK) cells are cytotoxic lymphocytes that express receptors specific for MHC class I molecules. The NK cell receptors belong to two structurally unrelated families, the killer cell Ig-like receptors and the killer cell C-type lectin receptors. We describe a cDNA clone derived from the bony (cichlid) fish Paralabidochromis chilotes and show that it encodes a protein related to the CD94/NK cell group 2 (NKG2) subfamily of the killer cell C-type lectin receptors. The gene encoding this receptor in a related species, Oreochromis niloticus, has a similar structure to the human CD94/NKG2 genes and is a member of a multigene cluster that resembles the mammalian NK cell gene complex. Thus, the CD94/NKG2 subfamily of NK cell receptors must have arisen before the divergence of fish and tetrapods and may have retained its function (possibly monitoring the expression of MHC class I molecules) for >400 million years.

Footnotes

↵ † To whom correspondence should be sent at the present address: Department of Anatomy (Division II), Tsurumi University, Yokohama 230-8501, Japan. E-mail: akie.sato{at}tuebingen.mpg.de.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations: BAC, bacterial artificial chromosome; CRD, carbohydrate-recognition domain; KLR, killer cell C-type lectin receptor; cKLR, cichlid KLR; NK, natural killer; NKC, NK cell gene complex; NKG2, NK cell group 2 receptors.
Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. AY297060–AY297086).