| A Stable Upstream Stem-loop Structure Enhances Selection of the First 5′-ORF-AUG as a Main Start Codon for Translation Initiation of Human ACAT1 mRNA |
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| 作者姓名： | Yang L Chen J Chang CC Yang XY Wang ZZ Chang TY Li BL |
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| 作者单位： | [1]StateKeyLaboratoryofMolecularBiology,InstituteofBiochemistryandCellBiology,ShanghailnstitutesforBiologicalSciences,theChineseAcademyofSciences,Shanghai200031China [2]DepartmentofBiochemistry,DartmouthMedicalSchool,Hanover,NH03756,USA |
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| 摘 要： | Human ACAT1 cDNA K1 was first cloned and functionally expressed in 1993. There are two adjacent in-frame AUG codons, AUG1397-1399 and AUG1415-1417, at 5′-terminus of the open reading frame (ORF,nt 1397-3049) of human ACAT1 mRNA corresponding to cDNA K1. In current work, these two adjacent in-frame AUGs at 5′-terminus of the predicted ORF (5′-ORF-AUGs) as start codons for translation initiation of human ACAT1 mRNA were characterized in detail. Codon mutations indicated that both of these two adjacent 5′-ORF-AUGs can be selected as start codons but the first 5′-ORF-AUG1397-1399 is a main start codon consistent with that of the predicted ORF of human ACAT1 mRNA. Further deletion and mutation analyses demonstrated that a stable upstream stem-loop structure enhanced the selection of the first 5′-ORF-AUG1397-1399 as a main start codon, in addition to upstream nucleotide A in the -3 position, which is a key site of Kozak sequence. In addition, result of ACAT1 enzymatic activity assay showed no obvious difference between these two ACAT1 proteins respectively initiated from the two adjacent 5′-ORF-AUGs. This work showed that astable upstream stem-loop structure could modulate the start codon selection during translation initiation of mRNAs that contain adjacent multi-5′-ORF-AUGs.
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| 关 键 词： | ACATl mRNA 人 启动密码子 基因 克隆 序列 |
A stable upstream stem-loop structure enhances selection of the first 5'-ORF-AUG as a main start codon for translation initiation of human ACAT1 mRNA |
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| Yang L,Chen J,Chang CC,Yang XY,Wang ZZ,Chang TY,Li BL.A stable upstream stem-loop structure enhances selection of the first 5'-ORF-AUG as a main start codon for translation initiation of human ACAT1 mRNA[J].Acta Biochimica et Biophysica Sinica,2004,36(4):259-268. |
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| Authors: | Yang Li Chen Jiang Chang Catherine C Y Yang Xin-Ying Wang Zhen-Zhen Chang Ta-Yuan Li Bo-Liang |
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| Institution: | State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, the Chinese Academy of Sciences. |
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| Abstract: | Human ACAT 1 cDNA K1 was first cloned and functionally expressed in 1993. There are two adjacent in-frame AUG codons, AUG(1397-1399) and AUG(1415-1417), at 5'-terminus of the open reading frame (ORF, nt 1397-3049) of human ACAT1 mRNA corresponding to cDNA K1. In current work, these two adjacent inframe AUGs at 5'-terminus of the predicted ORF (5'-ORF-AUGs) as start codons for translation initiation of human ACAT1 mRNA were characterized in detail. Codon mutations indicated that both of these two adjacent 5'-ORF-AUGs can be selected as start codons but the first 5'-ORF-AUG(1397-1399) is a main start codon consistent with that of the predicted ORF of human ACAT1 mRNA. Further deletion and mutation analyses demonstrated that a stable upstream stem-loop structure enhanced the selection of the first 5'-ORF-AUG(1397 -1399) as a main start codon, in addition to upstream nucleotide A in the -3 position, which is a key site of Kozak sequence. In addition, result of ACAT1 enzymatic activity assay showed no obvious difference between these two ACAT1 proteins respectively initiated from the two adjacent 5'-ORF-AUGs. This work showed that a stable upstream stem-loop structure could modulate the start codon selection during translation initiation of mRNAs that contain adjacent multi-5'-ORF-AUGs. |
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