MEK5α和MEK5β调控Beclin 1启动子  

MEK5α and MEK5β differentially regulate Beclin 1promoter

作　　者：刘晓芸 王雷斌 王庆[1] 张沙沙 赵微苗 贺林[1] 朱洪新 LIU Xiaoyun;WANG Leibin;WANG Qing;ZHANG Shasha;ZHAO Weimiao;HE Lin;ZHU Hongxin(Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders,Ministry of Education,Bio-X Institutes,Shanghai JiaoTong University,Shanghai 200240,China)

机构地区：[1]上海交通大学Bio-X研究院遗传发育与精神神经疾病教育部重点实验室,上海200240

出　　处：《上海大学学报（自然科学版）》2021年第3期563-572,共10页Journal of Shanghai University:Natural Science Edition

基　　金：国家自然科学基金资助项目(30971095)。

摘　　要：Beclin 1是哺乳动物自噬相关基因,调控自噬起始和自噬体成熟.在肌肉分化过程中,Beclin 1基因表达上调,自噬增加;此外MEK5-ERK5信号活化并调控成肌细胞分化.因此,在肌肉分化过程中,MEK5-ERK5信号通路可能调控Beclin 1基因表达.目的是阐明MEK5对成肌细胞Beclin 1基因启动子活性的调控.将不同长度Beclin 1启动子片段克隆至荧光素酶报告基因载体pGL3-Basic并转染成肌细胞C2C12.双荧光素酶报告基因检测实验结果显示,含Beclin 1基因起始密码子上游586碱基对DNA片段的载体(p-354)具有强荧光素酶活性.MEK5α显著增加p-354荧光素酶活性,并有剂量依赖性;而MEK5β显著降低p-354荧光素酶活性.MEK5β能够拮抗MEK5α对p-354荧光素酶活性的调控.与MEK5对Beclin 1基因启动子调控结果一致,MEK5αCA上调细胞Beclin 1 mRNA表达,MEK5βDD下调Beclin 1mRNA表达,并且MEK5βDD抑制MEK5αCA对Beclin 1 mRNA表达的促进作用.此外,转录因子CREB家族成员CREB3,CREBP和CREBL1能够显著上调p-354荧光素酶活性.CREB3呈剂量依赖性显著上调p-354荧光素酶活性,并与MEK5α具有协同效应.MEK5α和MEK5β对Beclin 1启动子具有不同调控作用,CREB可能是其下游效应因子.Beclin 1,a mammalian autophagy-related gene,regulates autophagy initiation and autophagosome maturation.During muscle differentiation,Beclin 1 is upregulated.Additionally,MEK5-ERK5 is activated to regulate muscle differentiation.Thus,MEK5-ERK5 may regulate Beclin 1 gene expression during muscle differentiation.The aim of this study was to determine MEK5 regulation of Beclin 1 promoter in myoblast cells.A series of promoter-luciferase constructs harbouring different lengths of Beclin 1 promoter were created and transfected into myoblast C2 C12 cells.In the luciferase assay,the construct containing 586 base pairs upstream of the start codon(p-354) exhibited the most potent luciferase activity.MEK5α and MEK5β enhanced and suppressed p-354 luciferase activity,respectively.MEK5β is capable of antagonizing the effect of MEK5α on p-354 luciferase activity.Consistent with the results on the regulatory effects of MEK5 on Beclin 1 promoter,MEK5αCA and MEK5βDD upregulated and downregulated Beclin 1 mRNA expression,respectively.Moreover,MEK5βDD antagonised the stimulatory effects of MEK5αCA on Beclin 1 mRNA expression.Members of the CREB family,including CREB3,CREBP,and CREBL1,promoted p-354 luciferase activity.Furthermore,CREB3 dose-dependently increased p-354 luciferase activity and exhibited a synergistic effect with MEK5α on p-354 luciferase activity.Collectively,these findings indicate that MEK5α and MEK5β differentially regulate Beclin 1 promoter activity and that CREB family members may be downstream effectors.

关 键 词：MEK5 Beclin 1 启动子 荧光素酶报告基因 

分 类 号：Q813.1[生物学—生物工程]