A molecule in teleost fish, related with human MHC-encoded G6F, has a cytoplasmic tail with ITAM and marks the surface of thrombocytes and in some fishes also of erythrocytes
- Authors
- Ohashi, K., Takizawa, F., Tokumaru, N., Nakayasu, C., Toda, H., Fischer, U., Moritomo, T., Hashimoto, K., Nakanishi, T., and Dijkstra, J.M.
- ID
- ZDB-PUB-130220-1
- Date
- 2010
- Source
- Immunogenetics 62(8): 543-559 (Journal)
- Registered Authors
- Ohashi, Ken
- Keywords
- MHC, G6F, ITAM, thrombocyte, erythrocyte, fish
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Blood Platelets/immunology
- Chromosome Mapping
- Erythrocytes/immunology
- Evolution, Molecular
- Fish Proteins/chemistry
- Fish Proteins/genetics*
- Fish Proteins/immunology*
- Fishes/genetics*
- Fishes/immunology*
- GATA1 Transcription Factor/genetics
- Gene Expression
- Goldfish/genetics
- Goldfish/immunology
- Humans
- Immunoglobulins/chemistry
- Immunoglobulins/genetics*
- Major Histocompatibility Complex*
- Molecular Sequence Data
- NF-E2 Transcription Factor/genetics
- Oncorhynchus mykiss/genetics
- Oncorhynchus mykiss/immunology
- Oryzias/genetics
- Oryzias/immunology
- Sequence Homology, Amino Acid
- Species Specificity
- PubMed
- 20614118 Full text @ Immunogenetics
In teleost fish, a novel gene G6F-like was identified, encoding a type I transmembrane molecule with four extracellular Ig-like domains and a cytoplasmic tail with putative tyrosine phosphorylation motifs including YxN and an immunoreceptor tyrosine-based activation motif (ITAM). G6F-like maps to a teleost genomic region where stretches corresponding to human chromosomes 6p (with the MHC), 12p (with CD4 and LAG-3), and 19q are tightly linked. This genomic organization resembles the ancestral “Ur-MHC” proposed for the jawed vertebrate ancestor. The deduced G6F-like molecule shows sequence similarity with members of the CD4/LAG-3 family and with the human major histocompatibility complex-encoded thrombocyte marker G6F. Despite some differences in molecular organization, teleost G6F-like and tetrapod G6F seem orthologous as they map to similar genomic location, share typical motifs in transmembrane and cytoplasmic regions, and are both expressed by thrombocytes/platelets. In the crucian carps goldfish (Carassius auratus auratus) and ginbuna (Carassius auratus langsdorfii), G6F-like was found expressed not only by thrombocytes but also by erythrocytes, supporting that erythroid and thromboid cells in teleost fish form a hematopoietic lineage like they do in mammals. The ITAM-bearing of G6F-like suggests that the molecule plays an important role in cell activation, and G6F-like expression by erythrocytes suggests that these cells have functional overlap potential with thrombocytes.