人源COX7A2L基因型的鉴定及其对线粒体功能与超级复合体组装的影响  

Identification of Human COX7A2L Genotypes and Their Effects on Mitochondrial Function and Assembly of Supercomplex

作　　者：葛玲虹 李文娜 黄佳涛 吕建新[1,2] Ge Linghong;Li Wenna;Huang Jiatao;Lu Jianxin(School of Laboratory Medicine and Life Sciences,Wenzhou Medical University,Wenzhou 325035,China;Hangzhou Medical College,Hangzhou 310053,China)

机构地区：[1]温州医科大学检验医学院生命科学学院,温州325035 [2]杭州医学院,杭州310053

出　　处：《中国细胞生物学学报》2018年第8期1303-1311,共9页Chinese Journal of Cell Biology

基　　金：国家自然科学基金(批准号:31670784)资助的课题~~

摘　　要：COX7A2L是一个线粒体呼吸链复合体IVCOX7A2亚基的类似蛋白。已知COX7A2L蛋白能够影响小鼠线粒体的功能,然而,关于该蛋白在哺乳动物细胞中功能亚型的分布及其如何影响线粒体的功能仍不清楚。为了明确COX7A2L蛋白在人源细胞中的表达类型及功能,该文初步分析了COX7A2L在人体细胞中亚型的表达情况及其对线粒体功能和超级复合体组装的影响。该文利用细胞生物学及分子生物学技术,发现COX7A2L在人体细胞中以单一亚型的形式表达并定位于线粒体内膜。研究者对96个中国人COX7A2L基因的测序分析后发现,COX7A2L基因的外显子上不存在任何多态性位点,提示COX7A2L基因序列以及功能在人群中高度保守。通过线粒体功能实验分析我们发现,COX7A2L基因敲除导致细胞线粒体呼吸功能减弱,ATP含量减少。随后的研究发现,人源COX7A2L同小鼠长亚型COX7A2L基因一样能够抑制超级复合体III+IV的组装,但是与小鼠COX7A2L长亚型不同的是,人源COX7A2L的基因敲除能够降低但不能完全去除超级复合体I+III+IV的含量,并且超级复合体III+IV的组装受到的影响远大于超级复合体I+III+IV。这提示,超级复合体I+III+IV的组装不完全依赖于COX7A2L蛋白的表达。综上所述,人源COX7A2L基因虽然对线粒体功能的影响类似于小鼠的长亚型COX7A2L,但是人源COX7A2L基因更保守,并且其对呼吸链超级复合体的影响不同于对应的鼠源基因。COX7 A2 L is a similar protein of the mitochondrial respiratory enzyme COX subunit 7 a. Two mouse strain specific COX7 A2 L isoforms differentially affect mitochondrial function, however, the regulatory role of COX7 A2 L in human mitochondrial function is not known. Here, we find that COX7 A2 L is expressed as a single isoform in human cells and located in the mitochondrial inner membrane. The sequence of COX7 A2 L is highly conserved, since no polymorphic sites are detected in 96 human subjects. Furthermore, we find both mitochondrial respiratory function and ATP content are decreased in COX7 A2 L knockout 293 T cells compared with wide type 293 T cells. Although our results indicate that loss of human COX7 A2 L inhibits the assembly of supercomplexIII＋IV, supercomplex In＋IIIn＋IVn assembly is differently affected, suggesting that supercomplex In＋IIIn＋IVn assembly is not completely dependent on the expression of COX7 A2 L. In summary, our data indicate that human COX7 A2 L is more conserved and plays a role like mouse long isoform of COX7 A2 L.

关 键 词：基因型 超级复合体组装 线粒体功能 

分 类 号：R394[医药卫生—医学遗传学]