载脂蛋白ApoD:系统发生、基因结构与表达调控

Apolipoprotein D:Phylogenetics,Gene Structure and Expression Regulation

载脂蛋白D(ApoD)属于脂蛋白家族,目前对ApoD的研究集中在基因表达、组织分布和具体功能上,而对其包括调控区在内的基因组结构分析相对较少,而该部分内容对进一步了解和阐明ApoD蛋白功能有重要意义。本文从生物信息学角度对分属于原生动物、无脊椎动物、头索动物和脊椎动物类群的10种动物ApoD的基因结构及调控区的调控元件的分析及比较,发现:(1)ApoD基因结构从原生动物草履虫到原口动物再到后口动物海胆的进化过程中不保守,但在分析的几种脊椎动物中相当保守;(2)文昌鱼ApoD基因扮演从无脊椎动物到脊椎动物承上启下的角色,代表脊椎动物ApoD基因原型;(3)调控区大多数调控元件为不同动物共有,说明ApoD功能及其表达调控在进化中的保守性;(4)ApoD基因个别调控元件是随着物种进化而出现并开始发挥相关作用,如SF-1;还有个别的调控元件在进化过程中还没有发现其规律,这可能说明A-poD的某些功能因物种不同存在一定差异。

Apolipoprotein D （ApoD） is a 29-kDa glycoprotein, a member of the lipocalin family. ApoD can bind small hydrophobic molecules such as cholesterol and arachidonic acid, etc. It also plays a role in many physiological and pathological processes such as the development and differertiation of the embryo, the apoptosis ＇bf cancer cells; immune defense, and so on. The study of ApoD gene has largely focused on its expression and function, but information regarding its genomic orgnization and regulatory elements which are significant in the research of its function is very much limited. In this study, the genomic structure and regulatory elements of ApoD from 9 representive species including protozoans, invertebrates, protochordates and vertebrates were analyzed and compared. The genonic structure of ApoD is less conservative in organisms from protozoans to deuterostomes, while it is highly conserved among chordates including amphioxuses and vertebrates. The majority of regulatory elements are present in all organisms ranging from unicellular protozoans to mammals, suggesting that ApoD plays a very fundamental role, and possesses a conserved regulatory mechanism. However, there are also some specific regulatory elements, which are present only in certain species, and may perform some special roles.