Section outline

  • General

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  • 基因表达式

    What you will learn 
    ::你会学到什么

    • Gene expression and how it is regulated
      ::Gene 表达式及其如何规范
    • Regulatory proteins and their role in gene expression
      ::管制性蛋白质及其在基因表达中的作用

    Person demonstrating a surprised or excited expression with raised hands and an open mouth.

    Can your expression change at any moment?
    ::您的表达式随时会改变吗 ?

    As you know, a person's expression can change moment by moment. The expression that is demonstrated is usually appropriate for that moment's feelings. Gene expression is the use of a gene whose product is necessary for that moment. It may be a moment during , it may be a moment of increased anxiety, or it may be in response to an environmental change. Whenever a particular is needed, gene expression provides it.
    ::如您所知, 一个人的表达方式可以瞬间改变。 所展示的表达方式通常适合这一时刻的情感。 基因表达方式是使用一个其产品对于这一时刻是必要的基因。 可能是在..., 可能是在..., 可能是更焦虑的瞬间, 也可能是环境变化的反应。 当需要某个特定的东西时, 基因表达方式提供它。

    Gene Expression
    ::基因表达式

    Each of your has at least 20,000 genes. In fact, all of your cells have the same genes. Do all of your cells make the same proteins? Obviously not. If they did, then all your cells would be alike. Instead, you have cells with different structures and functions. This is because different cells make different proteins. They do this by using or expressing, different genes. Using a gene to make a protein is called gene expression .
    ::您的每个细胞至少有20,000个基因。 事实上, 您所有的细胞都有相同的基因。 您所有的细胞都做同样的蛋白质吗? 显然没有。 如果是, 那么所有的细胞都是一样的。 相反, 您的细胞有不同的结构和功能。 这是因为不同的细胞会做不同的蛋白质。 它们通过使用或表达不同的基因来这样做。 使用基因来制造蛋白质被称为基因表达。

    How Gene Expression is Regulated
    ::如何管制 Gene 表达式

    Gene expression is regulated to ensure that the correct proteins are made when and where they are needed. Regulation may occur at any point in the expression of a gene, from the start of to the processing of a protein after . Following is a list of stages where gene expression is regulated:
    ::基因表达方式受管制,以确保正确的蛋白质在需要的时候和地点产生,在基因表达方式的任何时候,从开始到蛋白质处理,都可以有管制。

    • Chemical and structural modification of or chromatin
      ::或染色胺的化学和结构改变
    • Transcription
      ::翻译
    • Translation
      ::笔译 笔译
    • Post-transcriptional modification
      ::过时修改
    • transport
      ::运输、运输、运输、运输
    • mRNA degradation
      ::mRNA降解
    • Post-translational modifications
      ::翻译后修改

    As shown in the  Figure , transcription is controlled by regulatory proteins binding to the DNA. Specifically, gene regulation at the level of transcription controls when transcription occurs as well as how much RNA is created. A regulatory protein, or a transcription factor , is a protein involved in regulating gene expression. It is usually bound to a cis-regulatory element , which is part of the DNA. Regulatory proteins often must be bound to a cis-regulatory element to switch a gene on ( activator ), or to turn a gene off ( repressor ).
    ::如图所示,转录由与DNA挂钩的监管性蛋白控制,具体来说,当转录发生时,基因在转录控制层面的监管以及创造多少RNA。调制性蛋白或转录系数是管理基因表达方式所涉及的蛋白质。通常,转录受DNA一部分的精密监管性元素的约束。监管性蛋白通常必须受剪切基因(活化器)或关闭基因(压缩机)的精密监管性元素的约束。

    Transcription of a gene by RNA polymerase can be regulated by at least five mechanisms:
    ::由RNA聚合酶对基因的移植至少可以通过五个机制加以管制:

    • (proteins) alter the specificity of RNA polymerase for a promoter or set of promoters, making it more or less likely to bind to the promoter and begin transcription.
      :sad蛋白质)改变RNA聚合酶对促销者或成套促销者的特殊性,使其或多或少有可能与促销者捆绑并开始转录。
    • Activator proteins enhance the interaction between RNA polymerase and a particular promoter.
      ::活性蛋白增强RNA聚合酶与某一特定促销者之间的互动。
    • Repressor proteins bind to non-coding sequences on the DNA that are close to or overlap the promoter region, impeding RNA polymerase's progress along the strand.
      ::压缩蛋白质与DNA上接近或重叠的脱氧核糖核酸非编码序列捆绑在一起,阻碍RNA聚合酶沿链条的进展。
    • Basal factors are transcription factors that help position RNA polymerase at the start of a gene.
      ::Basal因素是转录系数,有助于RNA聚合酶在基因初始的位置。
    • Enhancers are sites on the DNA strand that are bound by activators in order to loop the DNA, bringing a specific transcription factor to the initiation complex . An initiation complex is composed of RNA polymerase and numerous (usually more than one) transcription factors.
      ::增强器是DNA线上的站点,它们受活性剂的约束,以便连接DNA,将具体的转录因子带入启动综合体,启动综合体由RNA聚合酶和许多(通常不止一个)转录因子组成。

    As the organism grows more sophisticated, gene regulation becomes more complex, though prokaryotic organisms possess some highly regulated systems. Some human genes are controlled by many activators and repressors working together. Obviously, a in a cis-regulatory region, such as the promoter, can greatly affect the proper expression of a gene. It may keep the gene permanently off, such that no protein can be made, or it can keep the gene permanently on, such that the corresponding protein is constantly made. Both of these can have detrimental effects on the cell.
    ::随着有机体的日益成熟,基因监管变得更加复杂,尽管蛋白质生物拥有一些高度监管的系统。 有些人类基因由许多活性者和抑制者共同控制。 显然,像促进者这样的CIS监管区可以极大地影响基因的正确表达方式。 它可能永久保存基因,从而无法制造蛋白质,或者可以永久保存基因,从而不断制造相应的蛋白质。 这两种基因都可能对细胞产生有害影响。

    Gene regulation by activators and repressors interacting with DNA during transcription.
    Regulation of Transcription. Regulatory proteins bind to regulatory elements to control transcription. The regulatory elements are embedded within the DNA.

     

     

     

    Summary
    ::摘要

    • Gene transcription is controlled by regulatory proteins that bind to regulatory elements on DNA.
      ::基因转录由受DNA监管要素约束的管制性蛋白质控制。
    • The proteins usually either activate or repress transcription.
      ::蛋白质通常要么激活,要么抑制转录。

    Review
    ::回顾

    1. What is gene expression?
      ::什么是基因表达?
    2. Why is gene expression regulated?
      ::为什么基因表达方式受管制?
    3. List three stages where gene expression is regulated.
      ::列出基因表达方式受管制的三个阶段。
    4. Describe how regulatory proteins regulate gene expression.
      ::说明管制性蛋白质如何调节基因表达方式。
    5. Compare activators to repressors.
      ::与压抑者相比的活化者。