第一节基因表达的基本条件 1、基因表达的基本过程 2、有效转录的基本条件 3、正确翻译的基本条件 4、影响克隆基因表达效率的因素
第一节 基因表达的基本条件 1、基因表达的基本过程 2、有效转录的基本条件 3、正确翻译的基本条件 4、影响克隆基因表达效率的因素
转录的具体过程 making an RNA copy of a DNA sequence RNA polymerase opens the part of the dna to be transcribed. Only one strand of dna (the template strand, antisense strand) is transcribed. TRANSCRIPTION top strand coding strand 33 sense strand DNA ATGCCGTTAGACCGTTAGCGGACCTGAC bottom strand 3 5 template strand m RNA antisense strand ynthesis 5 m RNA AUGCCGUU AGACCGUU AGCGGACCUGAC
Transcription(转录): making an RNA copy of a DNA sequence . RNA polymerase opens the part of the DNA to be transcribed. Only one strand of DNA (the template strand, antisense strand) is transcribed. 转录的具体过程
转录的具体过程 RNA polymerase Antisense strand 3 end of gene direction of transcription 5 end gene RNA DNA beginning of Pppl a gene RNA polymerase leaves DNA RNA molecules released Pa plepeQp RNA molecule 0今6 3 DNA rewinds
转录的具体过程 Antisense strand
有效转录的基本条件 Groups of genes coding for related proteins are arranged in units known as operons. An operon consists of an operator, promoter, regulator, and structural genes. The regulator gene codes for a repressor protein that binds to the operator, obstructing the promoter of the structural genes. The regulator does not have to be adjacent to other genes in the operon. If the repressor protein is removed, transcription may occur. Promoter for regulatory gene Regulatory Structural loci gene I: Promoter for lac operon Operator: Structural: Structural Structural gene for gene for 阝- galact gene for sidase β- galactoside:β galactoside transacetylase 半乳糖苷酶 permease 渗透酶 ac。。er。n 转乙酰基酶
有效转录的基本条件 Groups of genes coding for related proteins are arranged in units known as operons. An operon consists of an operator, promoter, regulator, and structural genes. The regulator gene codes for a repressor protein that binds to the operator, obstructing the promoter of the structural genes. The regulator does not have to be adjacent to other genes in the operon. If the repressor protein is removed, transcription may occur. 半乳糖苷酶 渗透酶 转乙酰基酶
First polypeptide Ribosome: mRNA Ribosomal subunits Initiation site Structural gene 1 Structural gene 2 Termination sig Second Third polypeptide polypeptide Structural gene 3 Structural Termination gene 2 Termination sign signal