树鼩BACE1全长编码序列的克隆及分子特征分析

Cloning a full-length coding sequence of BACE1 in tree shrews and prediction of its molecular characteristics

目的获取树鼩β-淀粉样前体蛋白切割酶BACE1(beta-site APP cleaving enzyme-1)的全长编码序列并进行分子特征分析,为开展AD疾病的机制研究提供依据。方法提取树鼩大脑及其他脏器组织总RNA,通过RACE(rapid-amplification of cDNA ends)实验得到的序列与中间序列进行拼接得到树鼩BACE 1全长编码序列,使用DNAMAN、MEGA 10.0.5、PyMOL等生物信息学软件,对其序列和分子特征进行分析。结果树鼩BACE 1除在脑组织表达外,在外周组织也有表达。树鼩BACE 1核酸序列和蛋白质分子整体结构与人类高度相似,树鼩与人类的BACE1蛋白在膜内结构区均存在一个高度保守的DXXLL的ACDL分选内吞基序,两者具有相同的胞外域、跨膜域及胞内域,但树鼩BACE1蛋白质相比人少一个潜在的乙酰基化位点,并且在折叠结构上存在差异。结论本研究获得树鼩BACE 1基因完整编码序列,其蛋白基本结构与人的基本相似,提示树鼩可能是作为研究AD病理改变或药物研究潜在的理想模型。

Objective To obtain the full-length coding sequence ofβ-amyloid precursor protein-cleaving enzyme(BACE1)and analyze its molecular characteristics.Methods Total RNAs from the brains and other organs of tree shrews were used.The full-length coding sequence of BACE 1 was obtained by splicing the sequence obtained via rapid amplification of cDNA ends(RACE)with the intermediate sequence.Sequence and molecular characteristic analyses were performed using DNAMAN,MEGA 10.0.5,PyMOL and other bioinformatics softwares.Results The BACE 1 nucleic acid sequence of tree shrews was highly similar to that of humans.The overall structures of the two protein molecules were highly similar and had the same extracellular,transmembrane and intracellular domains.Both the tree shrew and the human BACE1 proteins had a highly conserved ACDL sorting endocytic motif of DXXLL in the intramembranous domain.However,the tree shrew BACE1 protein had one potential acetylation site compared with that of humans and differed in its folding structure.Conclusions The complete coding sequence of the BACE 1 gene is obtained in our study,and the protein structure of tree shrews is similar to that of humans,suggesting that tree shrews may be an ideal model for studying pathological changes of Alzheimer’s disease or potential drug research.