T.13 Regulación de eucariotas por factores trans
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Questions and Answers

What is the primary role of transcription factors in gene expression?

  • To modify chromatin structure directly
  • To bind to specific DNA sequences and regulate transcription (correct)
  • To degrade RNA polymerase
  • To translate mRNA into proteins

    • Which of the following is a mechanism of transcriptional activation?

  • Modifying chromatin structure to make the gene less accessible
  • Blocking RNA polymerase from binding to the promoter region
  • Inhibiting transcription factor localization
  • Recruiting RNA polymerase to the promoter region (correct)

    • How can repressors decrease gene expression?

  • By phosphorylating RNA polymerase
  • By blocking RNA polymerase from binding to the promoter region (correct)
  • By interacting with coactivators
  • By degrading transcription factors

    • What is the role of cell signaling pathways in regulating transcription factors?

    <p>To activate transcription factors through phosphorylation</p> Signup and view all the answers

    What is the effect of chromatin remodeling on gene expression?

    <p>It can make genes more or less accessible to transcription factors</p> Signup and view all the answers

    What is the ultimate outcome of transcriptional activation and repression?

    <p>Changes in gene expression</p> Signup and view all the answers

    What is the primary difference in the complexity of regulatory sequences between bacterial and human genes?

    <p>Human genes have more complex and numerous regulatory sequences than bacterial genes.</p> Signup and view all the answers

    What type of elements are involved in regulating gene expression at a distance?

    <p>Enhancers</p> Signup and view all the answers

    What is the function of distal promoter sequences?

    <p>To regulate transcription at a distance</p> Signup and view all the answers

    What is the term used to describe regulatory elements that are specific to each gene?

    <p>Elementos de respuesta</p> Signup and view all the answers

    Where does transcription initiation occur in eukaryotic genes?

    <p>A little downstream of the promoter site</p> Signup and view all the answers

    What is the term used to describe elements that can both activate and repress transcription?

    <p>Potenciadores</p> Signup and view all the answers

    What is the purpose of the DNA condensing or forming loops in transcriptional activation?

    <p>To allow the formation of the transcription complex</p> Signup and view all the answers

    Why do eukaryotic activators have separate DNA-binding and activation regions?

    <p>To allow for independent functioning of the domains</p> Signup and view all the answers

    What is the function of the connector domain in the Gal4 protein?

    <p>To connect the DNA-binding and activation domains</p> Signup and view all the answers

    Why do transcription factors often have large, unstructured regions?

    <p>To allow for flexible binding to DNA</p> Signup and view all the answers

    What is the effect of dimerization on the recognition sequence of the Gal4 protein?

    <p>It increases the recognition sequence to 8 base pairs</p> Signup and view all the answers

    Why do transcription factors often have difficulty accessing certain DNA sequences?

    <p>Because of the compact structure of chromatin</p> Signup and view all the answers

    What is the probability of finding a specific 4-base pair sequence in DNA?

    <p>1 in 256</p> Signup and view all the answers

    What is the function of the zinc finger domain in the Gal4 protein?

    <p>To recognize specific DNA sequences</p> Signup and view all the answers

    Why do transcription factors often have regions of low structural complexity?

    <p>To allow for flexible binding to DNA</p> Signup and view all the answers

    What is the effect of the intrinsically disordered regions (IDR) on transcription factor binding?

    <p>It adds selectivity to the binding of transcription factors to DNA</p> Signup and view all the answers

    What is the main function of silencers in gene expression?

    <p>To inhibit the action of specific transcription factors</p> Signup and view all the answers

    What is the characteristic of general transcription factors?

    <p>They are highly conserved evolutionarily</p> Signup and view all the answers

    What is the role of proximal transcription factors?

    <p>To increase the efficiency of transcription initiation</p> Signup and view all the answers

    What is the function of the activator domain in a transcription factor?

    <p>To attract RNA polymerase to the promoter</p> Signup and view all the answers

    What is the characteristic of transcriptional activators?

    <p>They are composed of independent, modular domains</p> Signup and view all the answers

    What is the effect of inducible transcription factors on gene expression?

    <p>They can either increase or decrease gene expression</p> Signup and view all the answers

    What is the role of the structural domain in a transcription factor?

    <p>To provide a platform for protein-protein interactions</p> Signup and view all the answers

    What is the consequence of the modularity of transcription factors?

    <p>They can be manipulated to regulate gene expression</p> Signup and view all the answers

    What is the function of the connection domain in a transcription factor?

    <p>To facilitate the interaction between different domains</p> Signup and view all the answers

    What is the significance of the LexA protein in understanding transcriptional activators?

    <p>It is a transcriptional activator that can be manipulated to regulate gene expression</p> Signup and view all the answers

    What is the primary function of the disordered regions in transcription factors?

    <p>To facilitate the formation of liquid condensates, thereby enhancing the kinetics of DNA binding</p> Signup and view all the answers

    What is the role of the mediator in the transcriptional activation process?

    <p>To contact the transactivator and cover the RNA polymerase</p> Signup and view all the answers

    What is the mechanism by which transcription factors with intrinsic disorder regions increase their local concentration?

    <p>By forming liquid condensates</p> Signup and view all the answers

    What is the role of the Gal4 domain in the transcriptional activation process?

    <p>To serve solely as a DNA binding domain</p> Signup and view all the answers

    What is the outcome of replacing the Gal4 DNA binding domain with the LexA DNA binding domain?

    <p>The hybrid protein is able to activate transcription only when a LexA operator is placed near a promoter</p> Signup and view all the answers

    What is the role of the chromatin structure in the transcriptional process?

    <p>To select specific transcription factors</p> Signup and view all the answers

    What is the characteristic of the pseudorganelles formed by transcription factors with intrinsic disorder regions?

    <p>They are liquid condensates with distinct density properties</p> Signup and view all the answers

    What is the role of the coactivator in the transcriptional activation process?

    <p>To act as a bridge between the transcription factor and the RNA polymerase</p> Signup and view all the answers

    What is the consequence of increasing the local concentration of transcription factors?

    <p>The kinetics of DNA binding is increased</p> Signup and view all the answers

    What is the role of the double hybrid system in understanding transcriptional activation?

    <p>To demonstrate the modular architecture of transcription factors</p> Signup and view all the answers

    What is the location of the FT protein when it is in its active form?

    <p>In the nucleus</p> Signup and view all the answers

    What is the effect of the FT protein on gene expression?

    <p>It activates gene expression</p> Signup and view all the answers

    What is the role of the histone deacetylase (HDAC) in transcriptional repression?

    <p>It removes acetyl groups from histones</p> Signup and view all the answers

    How do repressors interact with the DNA to prevent gene expression?

    <p>They bind to the same site as the activator</p> Signup and view all the answers

    What is the ultimate effect of the desacetilation of nucleosomas on gene expression?

    <p>It represses gene expression</p> Signup and view all the answers

    What is the role of the FT protein in the nucleus?

    <p>It activates gene expression</p> Signup and view all the answers

    What is the mechanism of action of a repressor that binds to a site overlapping with the activator binding site?

    <p>It competes with the activator for binding to the DNA</p> Signup and view all the answers

    What is the effect of the acetilation of nucleosomas on gene expression?

    <p>It activates gene expression</p> Signup and view all the answers

    How do repressors interact with the activator to prevent gene expression?

    <p>They interact with the activator to form a heterodimer</p> Signup and view all the answers

    What is the main effect of activators on the basal apparatus?

    <p>Influencing the assembly of the basal apparatus</p> Signup and view all the answers

    What is the role of the maquinaria de transcripción in the repression of gene expression?

    <p>It interacts with the repressor to prevent gene expression</p> Signup and view all the answers

    Which general transcription factor is most frequently targeted by activators?

    <p>TFIID</p> Signup and view all the answers

    What is the role of TAFs in the basal apparatus?

    <p>Establishing the connection between the basal apparatus and activators</p> Signup and view all the answers

    Why is TBP alone unable to sustain high levels of transcriptional activation?

    <p>TBP requires TAFs or TFIID to facilitate transcriptional activation</p> Signup and view all the answers

    What is the purpose of importins in the regulation of activators?

    <p>To transport activators from the cytoplasm to the nucleus</p> Signup and view all the answers

    How can protein kinases influence the activity of activators?

    <p>By phosphorylating and activating activators</p> Signup and view all the answers

    What is the purpose of fosforilation in the regulation of activators?

    <p>To activate the activity of activators</p> Signup and view all the answers

    How can the activity of a inducible activator be regulated?

    <p>All of the above</p> Signup and view all the answers

    What is the role of NF-kB in transcriptional regulation?

    <p>It is an activator of transcriptional activity</p> Signup and view all the answers

    What is the consequence of the fragmentation of a precursor protein into an active activator?

    <p>The activator is activated</p> Signup and view all the answers

    What is the result of a signal arriving at a cell?

    <p>A second messenger is induced to enter the cell through a different mechanism.</p> Signup and view all the answers

    What is the term for a set of genes that code for a transcription factor and its target genes?

    <p>Regulon</p> Signup and view all the answers

    What is the primary objective of Molecular Systems Biology?

    <p>To obtain a mathematical model that can predict cellular behavior.</p> Signup and view all the answers

    What is the term for the study of the design principles of transcriptional regulatory networks?

    <p>Molecular Systems Biology</p> Signup and view all the answers

    What is the benefit of the design principles of transcriptional regulatory networks?

    <p>They have favored evolutionary autorregulation and benefited cells.</p> Signup and view all the answers

    What is the goal of modeling transcriptional regulatory networks?

    <p>To predict how cells will respond to signals.</p> Signup and view all the answers

    What is the role of metallothionein in response to toxic ions?

    <p>To chelate and remove toxic ions from the cell</p> Signup and view all the answers

    What induces the expression of metallothionein?

    <p>Any of the above</p> Signup and view all the answers

    How do steroid hormones enter the nucleus?

    <p>Through a receptor-mediated process</p> Signup and view all the answers

    What is the role of the second messenger in steroid hormone signaling?

    <p>To amplify the signal</p> Signup and view all the answers

    What is the specific region of the DNA sequence recognized by the receptor?

    <p>The half-site region</p> Signup and view all the answers

    How do transcription factors interact with each other?

    <p>Through hydrophobic interactions</p> Signup and view all the answers

    What is the term used to describe the network of mechanisms that regulate gene expression?

    <p>Regulatory network</p> Signup and view all the answers

    What is the role of the zinc fingers in steroid hormone receptors?

    <p>To recognize the DNA sequence</p> Signup and view all the answers

    What is the consequence of multiple signals simultaneously activating transcription factors?

    <p>The transcription factor is activated, and multiple genes are transcribed</p> Signup and view all the answers

    What is the characteristic of the promoter region in eukaryotic genes?

    <p>It is long and complex</p> Signup and view all the answers

    Study Notes

    Eukaryotic Regulation by Transcription Factors

    Gene Expression

    • Gene expression is the process by which the information in a gene is converted into a functional product, such as a protein
    • Transcription factors play a crucial role in regulating gene expression by binding to specific DNA sequences and either activating or repressing transcription

    Transcriptional Activation

    • Transcriptional activation occurs when a transcription factor binds to an enhancer or promoter region, increasing gene expression
    • Activators can:
      • Recruit RNA polymerase to the promoter region
      • Modify chromatin structure to make the gene more accessible
      • Interact with coactivators to enhance transcription

    Repression Mechanisms

    • Transcriptional repression occurs when a transcription factor binds to a silencer or promoter region, decreasing gene expression
    • Repressors can:
      • Block RNA polymerase from binding to the promoter region
      • Modify chromatin structure to make the gene less accessible
      • Interact with corepressors to inhibit transcription

    Cell Signaling Pathways

    • Transcription factors can be regulated by cell signaling pathways, which allow cells to respond to changes in their environment
    • Signaling pathways can:
      • Activate transcription factors through phosphorylation or other post-translational modifications
      • Inhibit transcription factors through degradation or sequestration
      • Regulate transcription factor localization or activity

    Chromatin Remodeling

    • Chromatin remodeling complexes can alter chromatin structure to make genes more or less accessible to transcription factors
    • Chromatin remodeling can:
      • Allow transcription factors to bind to previously inaccessible DNA sequences
      • Prevent transcription factors from binding to specific DNA sequences
      • Regulate gene expression by modifying chromatin structure

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    Description

    Learn about the regulation of gene expression in eukaryotes through transcription factors, including transcriptional activation and repression mechanisms, cell signaling pathways, and chromatin remodeling.

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