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
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
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DOI：
10.1007/s00251-010-0460-1
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发表时间：
2010-08-01
期刊：
影响因子：
3.2
通讯作者：
Dijkstra, Johannes Martinus
中科院分区：
文献类型：
--
作者：
Ohashi, Ken;Takizawa, Fumio;Dijkstra, Johannes Martinus
在硬骨鱼中，鉴定了一种新的基因G6 F-like，其编码具有四个胞外Ig样结构域和一个胞质尾区的I型跨膜分子，所述胞质尾区具有推定的酪氨酸磷酸化基序，包括YxN和基于免疫受体酪氨酸的激活基序（ITAM）。G6 F样图谱定位于硬骨鱼基因组区域，其中对应于人类染色体6p（具有MHC）、12 p（具有CD 4和LAG-3）和19 q的延伸紧密连接。这种基因组组织类似于为有颌脊椎动物祖先提出的祖先“Ur-MHC”。推导出的G6 F样分子与CD 4/LAG-3家族成员以及人类主要组织相容性复合物编码的血小板标记物G6 F显示出序列相似性。尽管在分子组织上存在一些差异，但硬骨鱼G6 F样和四足动物G6 F似乎是同源的，因为它们映射到相似的基因组位置，在跨膜和细胞质区域中共享典型的基序，并且都由血小板/血小板表达。在鲫鱼（Carassius auratus auratus）和银鲫（Carassius auratus langsdorfii）中，发现G6 F样不仅在血小板中表达，而且在红细胞中表达，支持硬骨鱼中的红细胞和血栓细胞形成与哺乳动物一样的造血谱系。ITAM轴承G6 F样表明，该分子在细胞活化中起着重要的作用，和G6 F样表达的红细胞表明，这些细胞与血小板功能重叠的潜力。
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.