Diversity of CD2 subfamily receptors in cyprinid fishes

Publication date: 2012 Source:Results in Immunology, Volume 2 Author(s): Shiro Sameshima , Miki Nakao , Tomonori Somamoto CD2 family receptor (CD2f) is evolutionarily conserved and is widely expressed by various types of leukocytes. To elucidate the phylogenetic diversity of the CD2f, we characterized CD2f in teleosts using ginbuna crucian carp and zebrafish. The identified CD2f isoforms of the ginbuna carp (caauCD2f) exhibited high sequence similarity to the mammalian CD2 subsets CD48, CD244, and CD319, but it was difficult to classify them into their respective mammalian CD2f based on sequence similarity, the presence of an immunoreceptor tyrosine-based switch motif (ITSM), and phylogenetic tree analysis. Although the four caauCD2f isoforms share an extracellular domain with quite high identity (83–94% identity at the nucleic acid level), they differ in the number of ITSM motifs in their cytoplasmic tail. RT-PCR and in situ hybridization analyses showed that the caauCD2f isoforms are expressed by different cell populations, suggesting that they, like mammalian CD2f, have diverse roles. Interestingly, immunoglobulin (Ig) domain-like sequences with high identity to caauCD2fs are clustered close together within 0.6Mbp on zebrafish chromosomes 1 and 2 (at least 8 and 35 sequences, respectively), and many pairs of the Ig domains share more than 90% identity at the amino acid level. Therefore, the teleost CD2fs with considerably high identity have been probably generated...
Source: Results in Immunology - Category: Allergy & Immunology Source Type: research