Department of Pediatrics, University of South Florida College of Medicine, USF/ACH Children's Research Institute, 140 7th Avenue South, St. Petersburg, FL 33701, USA.
Genomics. 2012 May;99(5):282-91. doi: 10.1016/j.ygeno.2012.02.004. Epub 2012 Feb 21.
A heretofore-unrecognized multigene family encoding diverse immunoglobulin (Ig) domain-containing proteins (DICPs) was identified in the zebrafish genome. Twenty-nine distinct loci mapping to three chromosomal regions encode receptor-type structures possessing two classes of Ig ectodomains (D1 and D2). The sequence and number of Ig domains, transmembrane regions and signaling motifs vary between DICPs. Interindividual polymorphism and alternative RNA processing contribute to DICP diversity. Molecular models indicate that most D1 domains are of the variable (V) type; D2 domains are Ig-like. Sequence differences between D1 domains are concentrated in hypervariable regions on the front sheet strands of the Ig fold. Recombinant DICP Ig domains bind lipids, a property shared by mammalian CD300 and TREM family members. These findings suggest that novel multigene families encoding diversified immune receptors have arisen in different vertebrate lineages and affect parallel patterns of ligand recognition that potentially impact species-specific advantages.
在斑马鱼基因组中鉴定出了一个以前未被识别的多基因家族，该家族编码多种免疫球蛋白（Ig）结构域包含的蛋白质（DICPs）。二十九个不同的基因座定位于三个染色体区域，编码具有两类 Ig 胞外结构域（D1 和 D2）的受体型结构。DICPs 之间的 Ig 结构域、跨膜区域和信号基序的数量和序列有所不同。个体间的多态性和选择性 RNA 加工有助于 DICP 的多样性。分子模型表明，大多数 D1 结构域属于可变（V）类型；D2 结构域是 Ig 样的。D1 结构域之间的序列差异集中在 Ig 折叠前片链的高变区。重组 DICP Ig 结构域结合脂质，这是哺乳动物 CD300 和 TREM 家族成员的共同特性。这些发现表明，编码多样化免疫受体的新型多基因家族在不同的脊椎动物谱系中出现，并影响潜在影响物种特异性优势的平行配体识别模式。
