Name: how transcription regulators work together
Uploaded: 2023-04-30T18:28:46.000Z
Duration: 2 min 13 s
Channel: JoVE

K12 Standards

Alabama Course of Study Science

9-12

Biology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

9-12.B.1.2

cooperative-binding-of-transcription-regulators

Cooperative Binding of Transcription Regulators

Transcriptional regulators are proteins that recognize and bind to short sequences of DNA known as cis-regulatory sequences. Because these sequences are usually less than ten nucleotides long, the chances of the same sequence randomly occurring in the genome are very high.
Many regulators form a dimer pair in order to limit binding to random sequences. A dimer can bind sequences longer than ten nucleotides making it less likely that the sequence will be randomly present in the genome and increasing the binding specificity.
These regulatory dimers can either be a homodimer made of the same types of monomer or a heterodimer with different types of monomers.&#160; Because the pairs can be composed of different monomers, the various combinations allow binding to different sequences without needing new types of proteins.
When not bound to DNA, cooperative regulators exist as monomers that sometimes form dimers through weak, non-covalent interactions; however, these structures form tightly associated dimers when bound to DNA due to cooperative binding.
Cooperative binding is a phenomenon where the binding of a monomer to the cis-regulatory sequence increases the likelihood of a second regulat

cooperative binding of transcription regulators

Transcriptional regulators bind to specific cis-regulatory sequences in the&#160;DNA to regulate gene transcription. These cis-regulatory sequences are very short, usually less than ten nucleotide pairs in length. The short length means that there is a high probability of the exact same sequence randomly occurring throughout the genome.&#160; Since regulators can also bind to groups of similar sequences, this further increases the chances of random binding. Transcriptional regulators form dimers that bind to a sequence twice as long as a monomer binds, increasing the sequences and reducing the chances of random binding. Transcription regulator dimers can be homodimers or heterodimers. In solution, these cooperative regulators exist either as monomers or weakly linked dimers. However, when these monomers bind to an extended cis-regulatory sequence on the DNA, they form stable dimers.
Cooperativity is a phenomenon where the binding of a monomeric protein causes structural changes to the DNA and increases the regulatory sites&#8217; affinity for other monomers. This enables the monomers to bind as dimers on the cis-regulatory sequence.&#160; This phenomenon also helps regulators access sites located on DNA that is tightly bound to histone proteins in the nucleosome, which would otherwise be inaccessible. The first binding usually occurs at the DNA at the end of the nucleosome, where it is not tightly bound. Binding at this site leads to the DNA moving away from the histones, thereby leading to the unpacking of the nucleosome. This unpacking increases access to the other regulatory sites. In eukaryotes, transcription factor binding predominantly depends on cooperativity.&#160; Although cooperativity can occur in some cases, most of the binding of transcriptional regulators in prokaryotes is non-cooperative. In such cases, the regulators exist as stable dimers held together by several non-covalent interactions.
Whether an unknown regulator binds cooperatively or non-cooperatively can be determined by plotting the number of occupied binding sites on the DNA against the protein concentration. If the plot is an S-shaped curve, it indicates that the regulator binds cooperatively to the binding sites.&#160; If the curve rises steadily before leveling off as it approaches all of the binding sites being occupied, it indicates that binding is non-cooperative.

Transcriptional regulators bind to specific cis-regulatory sequences in the&#160;DNA to regulate gene transcription. These cis-regulatory sequences are ...

Education

JoVE Core

Cell Biology

Unit 1

Control of Gene Expression

KEY TERMS AND CONCEPTS

how transcription regulators work together

Transcription regulators can bind cooperatively to control gene expression. In cooperative binding, the binding of one regulator can make it easier for another regulator to bind nearby DNA. This shared effect helps cells fine-tune when genes are turned on or off.

The topic also connects to how regulators interact with each other and with DNA. These interactions can strengthen binding at a target site. They can also change how strongly a gene is controlled in a specific cell or condition.

Understanding cooperative binding helps explain why gene regulation is often more precise than a single regulator acting alone. It shows how multiple transcription regulators can work together to shape gene activity.

How Transcription Regulators Work Together

how-transcription-regulators-work-together

cell specific gene expression

Cell-Specific Gene Expression in Development

Cell-specific gene expression helps explain how different cells make different proteins, even when they contain the same DNA. This process is central to development and to the way specialized tissues form. Gene expression is controlled by regulatory signals that turn particular genes on or off in specific cells. As a result, one cell can follow a different molecular program from another cell in the same organism. These differences help create the variety of cell types needed for normal...

regulation of expression occurs at multiple steps

regulation-of-expression-occurs-at-multiple-steps

Gene Expression Control at Every Stage

Gene expression control happens at several stages. Cells can change when a gene is active and how much product it makes. This regulation helps the cell respond to changing needs. One major control point is transcription. In eukaryotes, transcription can be regulated before it starts. It can also be regulated while it is already underway. These steps help determine whether a gene is copied into RNA. Cells can also regulate expression after transcription. The RNA may be processed, moved, or...

cis-regulatory sequences

DNA Switches That Control Gene Expression

Cis-regulatory sequences are DNA switches that help control gene expression. They do not code for proteins. Instead, they can turn nearby genes on or off and help determine when a gene is active. These sequences include promoters and enhancers. They are often found near the genes they regulate, and their effect depends on where they are in the genome. Because they work through DNA itself, they help cells control which genes are used in different situations. Cis-regulatory sequences are an...

Transcription regulators can bind cooperatively to control gene expression. In cooperative binding, the binding of one regulator can make it easier for another regulator to bind nearby DNA. This shared effect helps cells fine-tune when genes are turned on or off. The topic also connects to how regulators interact with each other and with DNA. These interactions can strengthen binding at a target site. They can also change how strongly a gene is controlled in a specific cell or condition. <br...

prokaryotic transcriptional activators and repressors

prokaryotic-transcriptional-activators-and-repressors

How Prokaryotic Gene Regulators Work

Prokaryotic gene regulators control transcription by helping or blocking RNA polymerase. Activators and repressors are two main types of regulatory proteins that influence whether a gene is expressed. These proteins let bacteria adjust gene activity in response to changing conditions. Activators help transcription start. They bind to specific DNA sequences near a promoter, which is the region where RNA polymerase begins transcription. By making RNA polymerase bind more easily, activators...

the eukaryotic promoter region

Promoter Sequences in Eukaryotes

Eukaryotic promoter sequences control where transcription begins. A promoter is a DNA region that helps start gene expression. In eukaryotes, this region is usually found upstream of the gene it regulates. The promoter contains specific DNA sequences that can bind proteins needed for transcription. These sequences help position RNA polymerase at the correct start site. They also help determine whether a gene is turned on at the right time and in the right cell type. Eukaryotic promoters can...

co-activators and co-repressors

Gene Regulation by Co-activators and Co-repressors

Co-activators and co-repressors help control gene expression. They do not usually bind DNA themselves. Instead, they work with transcription factors to change how strongly a gene is turned on or off. Co-activators support transcription. They help transcription factors and RNA polymerase work together, which can increase gene expression. Co-repressors do the opposite. They help reduce transcription and lower gene expression. These proteins are important because cells need precise control over...

master transcription regulators

Master Transcription Regulators in Gene Control

Master transcription regulators help control when genes turn on and off. These proteins sit at the top of gene regulation networks and shape how cells respond to signals. In many cases, they act early in development and influence which cell types form. These regulators bind DNA and affect transcription, which is the first step in making RNA from a gene. By turning transcription on or off, they can change the levels of many downstream genes at once. That broad effect makes them important for...

regulated mrna transport

mRNA Localization During Cell Control

mRNA localization helps cells move messenger RNA to specific places before proteins are made. This process is regulated, so the cell can control when and where a protein is produced. Messenger RNA, or mRNA, carries genetic instructions from DNA to the protein-making machinery. By transporting mRNA to a defined location, a cell can keep protein production focused where it is needed most. Regulated mRNA transport is an important part of this control. It links the movement of RNA with later...

mrna stability and gene expression

mRNA Degradation and Protein Output

mRNA degradation helps control how much protein a cell makes. Messenger RNA, or mRNA, carries the genetic message from DNA to the ribosome, where proteins are built. When mRNA stays intact longer, it can be used more often. When it breaks down faster, protein production drops. Cells regulate mRNA stability with cis-acting elements. These are sequences within the mRNA itself that influence how long the message lasts. They can affect whether the mRNA is protected or targeted for decay. This...

micrornas

How miRNA Silences Genes

MicroRNA (miRNA) is a short regulatory RNA that helps control gene expression. It is transcribed from introns, which are non-coding parts of a gene, or from intergenic regions, which are stretches of DNA between genes. miRNA begins as a longer primary transcript and must go through several processing steps before it becomes active. The first transcript, called primary miRNA or pri-mRNA, folds back on itself to form a stem-loop structure. In the nucleus, the endonuclease Drosha shortens this...

small interfering rnas (sirna)

siRNA in Gene Silencing

Small interfering RNA, or siRNA, is a short RNA molecule that helps silence genes. It works after a gene has been copied into RNA, making it part of post-transcriptional gene silencing. Scientists study siRNA because it shows how cells can control which genetic messages are used. siRNA acts by guiding the cell to destroy a matching RNA message. This lowers the amount of protein that can be made from that message. The process is specific, because the siRNA must match the target RNA sequence...

lncrna - long non-coding rnas

Long Non-coding RNAs in Cell Control

Long non-coding RNAs, or lncRNAs, are RNA molecules that do not code for proteins. Instead, they can help control how genes are used in cells. This makes them important regulators of cell behavior. lncRNAs can work in several ways. Some influence chromatin modification, which changes how tightly DNA is packed and how easy it is for genes to be turned on or off. Others help guide the process of cell differentiation, when unspecialized cells develop into more specific cell types. Because of...

epigenetic regulation

DNA Methylation and X Inactivation

DNA methylation and X-chromosome inactivation help control which genes are turned on or off. These epigenetic changes alter the physical structure of DNA without changing the DNA sequence. They help each cell make only the proteins it needs. For example, bone growth proteins are not made in muscle cells. Epigenetic control is important for normal development. It also helps cells keep the right patterns of gene activity. When these controls fail, diseases can develop. Cancer is one example, but...

key terms and concepts

Learn how cooperative binding helps transcription regulators attach to DNA together and fine-tune gene expression in high school biology.

How Transcription Regulators Work Together | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

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Cytoplasm

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The Nucleus

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Endoplasmic Reticulum

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Ribosomes

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Lysosomes

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overview-of-myosin-structure-and-function

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ATP and Macromolecule Synthesis

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1. Engage in evidence-based argument to relate a cell's function to the structure, function, and diversity of its components. Examples: Muscle cells have a large number of mitochondria, which create energy for contraction in the form of ATP. Some plant cells have a large vacuole which is used for storage and transport of excess nutrients in changing environments.

9-12.B.1.1

What is Gene Expression?

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RNA Structure

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Transcription

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Bacterial RNA Polymerase

Eukaryotic RNA Polymerases

General Transcription Factors

Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of ...

RNA Polymerase II Accessory Proteins

Transcription Elongation Factors

pre-mrna-processing-modification-of-pre-mrna-ends

Pre-mRNA Processing: Modification of pre-mRNA Ends

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or ...

Pre-mRNA Processing: RNA Splicing

Chromatin Structure and RNA Splicing

Alternative RNA Splicing

Nuclear Export of mRNA

Transfer RNA Synthesis

Ribosomal RNA Synthesis

The Nucleolus

Additional Subnuclear Structures

Translation

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tRNA Activation

Initiation of Translation

Termination of Translation

Improving Translational Accuracy

Prokaryotic Transcriptional Activators and Repressors

Nonsense-mediated mRNA Decay

The Eukaryotic Promoter Region

Molecular Chaperones and Protein Folding

Co-activators and Co-repressors

The Proteasome

Master Transcription Regulators

Regulated Protein Degradation

Regulated mRNA Transport

Proteins: From Genes to Degradation

mRNA Stability and Gene Expression

Cell Specific Gene Expression

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns (non-coding regions of a gene) or intergenic regions (stretches of DNA present between ...

Regulation of Expression Occurs at Multiple Steps

Small interfering RNAs (siRNA)

Cis-regulatory Sequences

lncRNA - Long Non-coding RNAs

Epigenetic Regulation

Epigenetic changes alter the physical structure of the DNA without changing the genetic sequence and often regulate whether genes are turned on or off. ...

2. Obtain and evaluate information to explain the role of DNA and RNA in transcription and translation leading to protein synthesis and cellular function.

Nucleic Acids and Nucleotides

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9-12.B.1.2.a

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9-12.B.1.2.b

Recombinant DNA

c. Obtain, evaluate, and communicate information regarding how DNA and genetic technology apply to daily life. Examples: CRISPR can be used to develop species-specific pest control tools. GMO technology is used to produce drought-resistant plants to increase food supplies. Genetic screening is used in neonatal healthcare.

9-12.B.1.2.c

How Transcription Regulators Work Together

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