CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos genéticos, Universidade do Porto, Rua Padre Armando Quintas, 4485-661, Vairão, Portugal.
Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal.
Immunogenetics. 2019 Jan;71(1):25-33. doi: 10.1007/s00251-018-1079-x. Epub 2018 Aug 29.
The human S100A7 resides in the epidermal differentiation complex (EDC) and has been described as a key effector of innate immunity. In humans, there are five S100A7 genes located in tandem-S100A7A, S100A7P1, S100AL2, S100A7, and S100AP2. The presence of several retroelements in the S100A7A/S100A7P1 and S100A7/S100A7P2 clusters suggests that these genes were originated from a duplication around ~ 35 million years ago, during or after the divergence of Platyrrhini and Catarrhini primates. To test this hypothesis, and taking advantage of the high number of genomic sequences available in the public databases, we retrieved S100A7 gene sequences of 12 primates belonging to the Cercopithecoidea and Hominoidea (Catarrhini species). Our results support the duplication theory, with at least one gene of each cluster being identified in both Cercopithecoidea and Hominoidea species. Moreover, given the presence of an ongoing gene conversion event between S100A7 and S100A7A, a high rate of mutation in S100A7L2 and the presence of pseudogenes, we proposed a model of concerted and birth-and-death evolution to explain the evolution of S100A7 gene family. Indeed, our results suggest that S100A7L2 most likely suffered a neofunctionalization in the Catarrhini group. Being S100A7 a major protein in innate defense, we believe that our findings could open new doors in the study of this gene family in immune system.
人类 S100A7 位于表皮分化复合物（EDC）中，被描述为先天免疫的关键效应因子。在人类中，有五个 S100A7 基因串联排列，分别是 S100A7A、S100A7P1、S100AL2、S100A7 和 S100AP2。S100A7A/S100A7P1 和 S100A7/S100A7P2 簇中存在多个反转录元件表明，这些基因起源于大约 3500 万年前，在灵长类动物的 Platyrrhini 和 Catarrhini 分支之后或期间。为了验证这一假设，并利用公共数据库中可用的大量基因组序列，我们检索了属于 Cercopithecoidea 和 Hominoidea（Catarrhini 物种）的 12 种灵长类动物的 S100A7 基因序列。我们的结果支持了复制理论，在 Cercopithecoidea 和 Hominoidea 物种中都发现了每个簇的至少一个基因。此外，鉴于 S100A7 和 S100A7A 之间存在持续的基因转换事件，S100A7L2 中的突变率较高以及存在假基因，我们提出了一个协同和生死进化的模型来解释 S100A7 基因家族的进化。事实上，我们的结果表明，S100A7L2 很可能在 Catarrhini 组中经历了新功能化。S100A7 是先天防御的主要蛋白质，我们相信我们的研究结果可以为免疫系统中该基因家族的研究开辟新的途径。
