Serna-Duque Jhon A, Cuesta Alberto, Esteban M Ángeles
Immunobiology for Aquaculture Group, Department of Cell Biology and Histology, Faculty of Biology, Campus of International Excellence, Campus Mare Nostrum, University of Murcia, 30100, Murcia, Spain.
Immunobiology for Aquaculture Group, Department of Cell Biology and Histology, Faculty of Biology, Campus of International Excellence, Campus Mare Nostrum, University of Murcia, 30100, Murcia, Spain.
Fish Shellfish Immunol. 2022 May;124:563-571. doi: 10.1016/j.fsi.2022.04.032. Epub 2022 Apr 28.
Host defense peptides (HDP) are among the most ancient immune molecules in animals and clearly reflect an ancestral evolutionary history involving pathogen-host interactions. Hepcidins are a very widespread family of HDPs among vertebrates and are especially diverse in teleosts. We have investigated the identification of new hepcidins in gilthead seabream (Sparus aurata), a fish farmed in the Mediterranean. Targeted gene predictions supported with expressed sequence tags (ESTs) derived from Hidden Markov Models were used to find the hamp genes in the seabream genome. The results revealed a massively clustered hamp duplication on chromosome 17. In fact, the seabream genome contains the largest number of hepcidin copies described in any vertebrate. The evolutionary history of hepcidins in seabream, and vertebrates generally, clearly indicates high adaptation in teleosts and novel subgroups within hepcidin type II. Furthermore, basal hepcidin gene expression analysis indicates specific-tissue expression profiles, while the presence and distribution of transcription factor binding sites (TFBS) in hamp promoters as well as their transcription profile upon bacterial challenge indicates different immune roles depending on the type of hepcidin and tissue. This massive duplication of HDP genes in a bony fish could point to a far more specific and adaptive innate immune system than assumed in the classic concept of immunity in mammals. Hence, a new world of knowledge regarding hepcidins in fish and vertebrates is being initiated.
宿主防御肽（HDP）是动物中最古老的免疫分子之一，清楚地反映了涉及病原体与宿主相互作用的祖先进化史。铁调素是脊椎动物中非常广泛的一类HDP，在硬骨鱼中尤其多样。我们研究了在养殖于地中海的金头鲷（Sparus aurata）中鉴定新铁调素的方法。利用来自隐马尔可夫模型的表达序列标签（EST）支持的靶向基因预测，在金头鲷基因组中寻找铁调素基因（hamp）。结果显示在17号染色体上存在大量成簇的铁调素基因重复。事实上，金头鲷基因组中包含的铁调素拷贝数在所有脊椎动物中是最多的。金头鲷以及一般脊椎动物中铁调素的进化史清楚地表明，硬骨鱼具有高度适应性，且铁调素II型内出现了新的亚组。此外，基础铁调素基因表达分析表明其具有特定组织表达谱，而铁调素基因启动子中转录因子结合位点（TFBS）的存在和分布以及细菌攻击后的转录谱表明，根据铁调素类型和组织的不同，其具有不同的免疫作用。硬骨鱼中HDP基因的这种大量重复可能表明其先天免疫系统比哺乳动物免疫经典概念中所设想的更加特异和具有适应性。因此，一个关于鱼类和脊椎动物中铁调素的新知识世界正在开启。
