Name: rnai for gene silencing and discovery
Uploaded: 2021-04-07T12:12:00.000Z
Duration: 2 min 15 s
Channel: JoVE

K12 Standards

Tennessee Academic Standards

High School

Biology

links-among-engineering-technology-science-and-society

Links Among Engineering, Technology, Science, and Society

BIO1.ETS2.1

Experimental RNAi

RNA interference, or RNAi, is a process cells use to silence gene expression.&#160;
In this mechanism, an enzyme, Dicer, cleaves short hairpin RNA into short interfering RNA, or siRNA, approximately twenty-two base pairs in length.
This siRNA is picked up by an enzyme complex called the RNA induced silencing complex, or RISC, and converted into single-stranded RNA during risk assembly on its target mRNA.
The single-stranded RNA can hybridize with complementary mRNA. An enzyme in the RISC complex called Argonaute cleaves the target mRNA. The degradation of mRNA inhibits the translation process, resulting in gene silencing.
RNA interference has been used by researchers to study the function of various genes, such as the APC, a gene thought to be involved in cancer.&#160; A vector is constructed that codes for a short hairpin RNA that targets a specific mRNA transcript.
This vector can be added to cells or an organism to silence a gene.&#160; If the vector is introduced into the embryonic stem cells of mice, its sequence will be integrated into the host genome, producing transgenic mice.
These mice produce RNA from the inserted sequence that fold into hairpin structures. These structures are recognized by the RNAi machinery in the cytoplasm and are cleaved into double stranded RNA.
The RNA is then incorporated into RISC as a single-stranded RNA.&#160; RISC binds to the complementary sequence on a target mRNA transcript resulting in its degradation.
Mice with an inactivated APC gene develop tumors in their colon more often than control mice with a functional APC gene.&#160; This indicates that it is likely that APC is responsible for suppressing tumor growth.

experimental rnai

RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. The mechanism was discovered by Andrew Fire and Craig Mello in 1998 in plants. Today, it is observed in almost all eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. This precise cellular mechanism of gene silencing has been developed into a technique that provides an efficient way to identify and determine the function of several genes without genetically modifying the organism.
<h4>Applications of RNAi</h4>
RNAi helps in analyzing gene functions. For example, the RNAi technique helped screen chromosomes I and III of C.elegans and led to the identification of genes involved in cell division and embryonic development. This technology has also been successfully applied to Drosophila melanogaster to identify genes with essential roles in embryonic development, biochemical signaling cascades, and other fundamental cellular processes. In coffee plants, the gene responsible for producing theobromine synthase was knocked out using an RNA construct, producing decaffeinated coffee plants. Research shows that small interfering RNAs (siRNA) can inhibit infections caused by human immunodeficiency virus, hepatitis B virus, and poliovirus in cultured human cell lines. Researchers have also successfully knocked down genes expressed by the respiratory syncytial virus responsible for causing severe respiratory disease in infants and neonates.
<h4>Advantages of RNAi over conventional gene knockout</h4>
Before discovering RNAi technology, gene function was analyzed by knocking out the gene of interest from the genome and observing the phenotypic changes. While gene knockout is an irreversible method, RNAi is a reversible method that provides large-scale silencing of protein-coding genes in a genome. Moreover, it is a precise technique that can differentially silence genes even with a single nucleotide variation. Therefore, it can help in targeting dominant mutants like some oncogenes. Moreover, the RNAi technique is highly potent as the effector molecules function at a low concentration compared to the oligonucleotides or ribozymes used in the old method.

RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. ...

Education

JoVE Core

Molecular Biology

Unit 2

Analyzing Gene Expression and Function

KEY TERMS AND CONCEPTS

rnai for gene silencing and discovery

RNA interference (RNAi) is a gene-silencing process used to reduce gene expression. It can block transcription or trigger RNA degradation. Scientists first discovered this mechanism in plants in 1998 through Andrew Fire and Craig Mello.

RNAi has since been found in many eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. Researchers use it as a practical tool to study gene function. It can show what a gene does without permanently changing the organism’s DNA.

This method has helped scientists screen chromosomes I and III in C. elegans. Those studies identified genes involved in cell division and embryonic development. RNAi has also been used in Drosophila melanogaster to find genes that are important for embryonic development, biochemical signaling cascades, and other basic cellular processes.

RNAi also has real-world applications beyond gene studies. In coffee plants, an RNA construct was used to knock out the gene for theobromine synthase, which produced decaffeinated coffee plants. Small interfering RNAs, or siRNAs, have also been shown to inhibit infections caused by HIV, hepatitis B virus, and poliovirus in cultured human cell lines. Researchers have also knocked down genes expressed by respiratory syncytial virus, which causes severe respiratory disease in infants and neonates.

Compared with conventional gene knockout, RNAi has several advantages. A gene knockout removes a gene from the genome and is irreversible, while RNAi is reversible. It can silence large groups of protein-coding genes and can even distinguish genes that differ by a single nucleotide. This makes it useful for targeting dominant mutants such as some oncogenes. RNAi is also highly potent because its effector molecules work at low concentration, unlike the oligonucleotides or ribozymes used in older methods.

RNAi for Gene Silencing and Discovery

in vitro mutagenesis

In Vitro Mutagenesis for Gene Analysis

In vitro mutagenesis is a lab method used to change DNA and study gene function. It helps scientists test how specific DNA changes affect a gene’s activity and the traits it controls. A common approach is to make a known change in a DNA sequence and then examine the result. This can be done by deleting, inserting, or altering selected bases in a gene. The method is useful for linking a DNA change to a biological effect. Researchers use in vitro mutagenesis in molecular biology, genetics, and...

genetic screens

Using Genetic Screens to Find Disease Genes

Genetic screens are tools used to find genes and mutations linked to specific traits. They are also used to identify people or groups at risk for genetic diseases. That can support early intervention, targeted therapy, and reproductive choices. Forward genetic screens, also called classical screens, start with random DNA changes in an organism. Researchers may use radiation, mutagens, or added bases to create mutations that lead to visible phenotype changes. The mutant is then inbred so...

test cross

Test Cross in Genetic Inheritance

A test cross is a genetics tool used to determine the genotype of an organism with a dominant trait. It helps reveal whether the dominant individual is homozygous or heterozygous by crossing it with a recessive individual. The outcome of the cross shows the hidden genotype. If any offspring show the recessive trait, the dominant parent must carry one recessive allele. If all offspring show the dominant trait, the dominant parent is likely homozygous dominant. Test crosses are common in basic...

complementation tests

Using Crosses to Group Mutations

A complementation test uses a simple cross to find out whether two mutations are in the same gene or in different genes. It helps show how mutations are arranged on chromosomes. Edward Lewis first performed this test in the 1940s while studying fruit flies. To do the test, organisms heterozygous for different mutations are crossed pairwise in all combinations. If the mutations are in different genes, they can complement each other. In that case, each mutation provides the missing genetic...

single nucleotide polymorphisms-snps

SNPs as Genetic Markers and Variants

Single nucleotide polymorphisms, or SNPs, are small DNA changes at one specific genomic position. They are the most common type of sequence variation in the human genome. A point mutation counts as an SNP when it appears in more than 1% of the population.

bacterial transformation

Bacterial Transformation in the Lab

Bacterial transformation is a lab method used to move new DNA into bacteria. Scientists use it to change how bacteria behave or to help them carry a gene of interest. In high school biology, this process is often shown with plasmids, which are small circular DNA molecules. During transformation, bacteria take up DNA from their surroundings. The new DNA can then be used by the cell, depending on the experiment. This technique is an important part of genetic engineering and is widely used in...

transgenic organisms

Making Transgenic Organisms

Transgenic organisms are living things with DNA added from another organism. A transgene is the inserted gene. Scientists use this method to change an organism’s traits and to study how genes work. To make a transgenic organism, researchers first identify the gene they want to add. They then place that gene into the target organism’s DNA. Once the gene is integrated, the organism can pass it to new cells as it grows. This approach is useful in biology because it helps scientists analyze gene...

reproductive cloning

Cloning an Organism by Reproduction

Reproductive cloning creates a new organism that is genetically the same as the donor. It is different from cloning genes or cells because the goal is to make a whole living individual. This process usually relies on somatic cell nuclear transfer. In this method, the nucleus from a body cell is placed into an egg cell that has had its own nucleus removed. The egg can then develop into an embryo with DNA from the donor cell. Reproductive cloning is used to produce a copy of an organism, such...

crispr

CRISPR Gene Editing Basics

CRISPR is a gene editing tool that helps scientists make targeted changes to DNA. It uses a guide system to find a chosen sequence and a cutting protein to act at that spot. This method is based on a natural defense system found in bacteria. In high school biology, it is often studied as a way to see how genes can be edited with precision. CRISPR is widely used in molecular biology research. It helps scientists explore how genes function and how DNA changes can affect living things.

RNA interference (RNAi) is a gene-silencing process used to reduce gene expression. It can block transcription or trigger RNA degradation. Scientists first discovered this mechanism in plants in 1998 through Andrew Fire and Craig Mello. RNAi has since been found in many eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. Researchers use it as a practical tool to study gene function. It can show what a gene does without permanently changing the organism’s DNA. <br...

reporter genes

Reporter Genes in Cells and Plasmids

Reporter genes are protein-coding genes used to track gene activity in cells. They are often tagged to a gene of interest so scientists can see whether that gene is present or active. When the tagged genes are expressed together, reporter genes can produce visible signals such as fluorescence or luminescence. These signals help show the presence or absence of a gene of interest in an organism. They can also reveal the pattern of gene expression or the location of a DNA segment or protein...

in-situ hybridization

ISH Probes for DNA and RNA Detection

In situ hybridization (ISH) uses labeled probes to detect and localize specific DNA or RNA molecules in cells, tissues, or tissue sections. The probe is a complementary strand of DNA or RNA that binds to a matching nucleotide sequence in the sample. Since its first use in 1969 for nucleic acid studies, ISH has become an important tool in research and in clinical diagnosis. Several probe types can be used in ISH. These include single-stranded DNA probes, double-stranded DNA probes, antisense...

chromatin immunoprecipitation- chip

ChIP Methods for DNA-Protein Binding

Chromatin immunoprecipitation, or ChIP, is an antibody-based method for finding where proteins bind to DNA. It is used to identify DNA sites bound by transcription factors or histone proteins. ChIP also helps show which histone changes are present, including acetylation, phosphorylation, and methylation. ChIP is commonly divided into two forms: X-ChIP and N-ChIP. X-ChIP first cross-links proteins to DNA inside the cell, then breaks the DNA into pieces by sonication. The protein-DNA complexes...

synthetic biology

Synthetic Biology in Crops and Cells

Synthetic biology combines engineering, molecular biology, cell biology, and systems biology to redesign living systems. Scientists use it to remodel organisms from nature or to build new synthetic organisms. These tools can support protein or enzyme production, bioremediation, the production of useful macromolecules, and the addition of helpful traits to crops. One well-known example is golden rice. This genetically modified rice plant makes grains rich in β-carotene, which is a precursor of...

ribosome profiling

Ribosome Profiling for Translation Snapshot

Ribosome profiling is a deep sequencing method that gives a snapshot of active translation in a cell. It sequences the mRNAs protected by ribosomes. This shows which messages are being read to make proteins at a specific moment. The method has several uses in biology. It can track translation in a living organ or tissue type. It also helps measure new protein synthesis levels. Researchers use it to find translated open reading frames, which are stretches of RNA that can make protein. It can...

transgenic plants

Transgenic Plants for Better Crops

Transgenic plants are crops that have been changed with recombinant DNA technology, also called transgenesis. This method adds a foreign gene or removes a harmful one from an organism. The result is a genetically modified organism. The first transgenic plant was a tobacco plant made in 1983, and it was resistant to tobacco mosaic virus. Since then, transgenic plants have been developed for many uses in agriculture, horticulture, and ornamental plants. Some are designed to resist pests or...

gene therapy

Gene Therapy for Disease Treatment

Gene therapy is a treatment approach that changes gene activity to help address disease. It focuses on the genetic cause of a problem rather than only easing symptoms. In this way, it is used in disease intervention. One common strategy is to replace a faulty gene with a normal copy. Another strategy is to inactivate a gene that is causing harm. Gene therapy can also introduce a new gene to help cells work more normally.

epistasis analysis

Gene Interaction Maps in Epistasis

Gene interaction maps in epistasis show how different genes work together to shape a phenotype. In epistasis, the interaction of genes or alleles at different locations affects the final trait. This often happens when one gene masks or interferes with the expression of another gene. Epistasis is common when genes are part of the same biochemical pathway. In that case, the expression of one gene can depend on a gene product made earlier in the pathway. Genes that mask or inhibit other genes in...

genome-wide association studies-gwas

Using SNP Patterns to Link Disease Risk

Genome-wide association studies, or GWAS, look for common SNPs, or single nucleotide polymorphisms, that may be linked to disease. Researchers compare how often a SNP appears in people with a disease and in people without it. When a SNP is seen more often in the disease group, it is considered associated with that disease. GWAS uses chi-square analysis to test the chance that an allele is linked to the disease. This approach does not require scientists to first find the target gene behind the...

key terms and concepts

Explore how RNA interference silences genes, helps scientists study gene function, and supports applications from decaf coffee plants to antiviral research.

RNAi for Gene Silencing and Discovery | JoVE K12

molecular biology

JoVE Core Molecular Biology showcases the molecular processes of the cell through clear and concise animated video lessons. Additionally, in scientist-in-action videos, these concepts' application is demonstrated through real experiments in modern laboratories.

Virginia  Standards of Learning

HIgh School

BIO.5

BIO.5.e

Arizona Science Standards

Life Science

HS.L3

HS.L3U3.26

Molecular Cloning

Molecular cloning is a set of methods, which are used to insert recombinant DNA into a vector - a carrier of DNA molecules that will replicate recombinant ...

An Overview of Genetic Engineering

Genetic engineering &#8211; the process of purposefully altering an organism&#8217;s DNA &#8211; has been used to create powerful research tools and model ...

Recombineering and Gene Targeting

One of the most widely used tools in modern biology is molecular cloning with restriction enzymes, which create compatible ends between DNA fragments that ...

Genome Editing

A well-established technique for modifying specific sequences in the genome is gene targeting by homologous recombination, but this method can be ...

Recombinant DNA

DNA Ligation Reactions

In molecular biology, ligation refers to the joining of two DNA fragments through the formation of a phosphodiester bond.  An enzyme known as a ligase ...

Restriction Enzyme Digests

Restriction enzymes or endonucleases recognize and cut DNA at a specific sequence.  These enzymes occur naturally in bacteria as a defense against ...

DNA Isolation

DNA isolation protocols can be fast and straightforward or complex and time-consuming depending on the type and quality of DNA required for further ...

Restriction Enzymes

Restriction enzymes are bacterial enzymes used to cut DNA in a sequence-specific manner. To cleave DNA, they bind to specific palindromic sequences called ...

DNA Agarose Gel Electrophoresis

Agarose gel electrophoresis is a laboratory technique commonly used to separate DNA fragments by size. However, it can also be used to isolate and purify ...

DNA Gel Electrophoresis

DNA gel electrophoresis is a technique used for the detection and separation of DNA molecules. An electric field is applied to a gel matrix comprised of ...

Separating Protein with SDS-PAGE

Sodium Dodecyl Sulfate Poly-Acrylamide Gel Electrophoresis, or SDS-PAGE, is a widely-used technique for separating mixtures of proteins based on their ...

Plasmid Purification

Plasmid purification is a technique used to isolate and purify plasmid DNA from genomic DNA, proteins, ribosomes, and the bacterial cell wall. A plasmid ...

Gel Purification

Gel purification is used to recover DNA fragments after electrophoretic separation. DNA recovery from an agarose gel includes three basic steps: binding, ...

PCR - Polymerase Chain Reaction

Real Time RT-PCR

Real-time reverse transcription-polymerase chain reaction, or Real-time RT-PCR, is an analytical tool used to determine the expression level of target ...

RACE - Rapid Amplification of cDNA Ends

Rapid Amplification of cDNA Ends, or RACE, is one of the most effective methods to obtain a full-length cDNA from an mRNA sequence between a known ...

PCR: The Polymerase Chain Reaction

The polymerase chain reaction, or PCR, is a technique used to amplify DNA through thermocycling &#8211; cyles of temperature changes at fixed time ...

bacterial-transformation-the-heat-shock-method

Bacterial Transformation: The Heat Shock Method

Transformation is the process that occurs when a cell ingests foreign DNA from its surroundings. Transformation can occur in nature in certain types of ...

Bacterial Transformation: Electroporation

The term &#x201C;transformation&#x201D; refers cellular ingestion of foreign DNA.  In nature, transformation can occur in certain types of bacteria.  In ...

An Introduction to Transfection

Transfection is the process of inserting genetic material, such as DNA and double stranded RNA, into mammalian cells. The insertion of DNA into a cell ...

Labeling DNA Probes

DNA probes are fragments of DNA labeled with a reporter tag to enable their detection or purification. The resulting labeled DNA probes can then hybridize ...

Southern Blot

Agarose gel electrophoresis is very useful in separating DNA fragments by size. Running a DNA ladder containing fragments of the known length alongside ...

DNA Microarrays

Microarrays are high-throughput and relatively inexpensive assays that can be automated to analyze large quantities of data at a time. They are used in ...

An Overview of Gene Expression

Gene expression is the complex process where a cell uses its genetic information to make functional products. This process is regulated at multiple ...

Expression Profiling with Microarrays

Microarrays are important tools for profiling gene expression, and are based on complementary binding between probes that are attached to glass chips and ...

Complementary DNA

FISH - Fluorescent In-situ Hybridization

Fluorescence in situ hybridization, or FISH, was developed in the early 1980s and has quickly become one of the most widely used techniques in ...

Sanger Sequencing

DNA sequencing is a fundamental technique that is routinely used in the biological sciences. This method can be applied to a range of questions at ...

Maxam-Gilbert Sequencing

In the same year as the discovery of the Sanger sequencing method, another group of scientists, Allan Maxam and Walter Gilbert, demonstrated their ...

Next-generation Sequencing

The first human genome sequencing project cost $2.7 billion and was declared complete in 2003, after 15 years of international cooperation and ...

Chromatin Immunoprecipitation- ChIP

Chromatin immunoprecipitation, or ChIP, is an antibody-based technique used to identify sites on DNA that bind to transcription factors of interest or ...

RNA-seq

RNA sequencing, or RNA-Seq, is a high-throughput sequencing technology used to study the transcriptome of a cell. Transcriptomics helps to interpret the ...

Synthetic Biology

Synthetic biology is an interdisciplinary science that involves using principles from disciplines such as engineering, molecular biology, cell biology, ...

Genome Annotation and Assembly

The genome refers to all of the genetic material in an organism. It can range from a few million base pairs in microbial cells to several billion base ...

Ribosome Profiling

Ribosome profiling or ribo-sequencing is a deep sequencing technique that produces a snapshot of active translation in a cell. It selectively sequences ...

The ELISA Method

An enzyme-linked immunosorbent assay (ELISA) is typically performed to detect the presence and/or amount of a target protein of interest within an ...

Transgenic Plants

Recombinant DNA technology called transgenesis is often used to add a foreign gene or remove a detrimental gene from an organism. Such genetically ...

Transgenic Organisms

Gene Therapy

Reproductive Cloning

CRISPR

Reporter Genes

Reporter genes are a type of&#160;protein-coding gene&#160;that are often tagged to a gene of interest. Once inside a target cell, reporter genes usually ...

In-situ Hybridization

In situ hybridization (ISH) is a technique used to detect and localize specific DNA or RNA molecules in cells, tissue, or tissue sections using a labeled ...

Obtain, evaluate, and communicate information on how molecular biotechnology may be used in a variety of fields.
EXPLANATION: The goal is to help students appreciate that the basic science knowledge being studied can be manipulated and used to design useful tools for further scientific investigations, medical treatments, agricultural yields, etc. A detailed understanding of any technical procedures is not expected, but rather a "big picture" view of concepts the technology utilizes and the applications the technology is being used for. These technologies may be best investigated along with the standards from LS1 From Molecules to Organisms: Structure and Functions, as the students are learning about DNA and protein. Comparative DNA and protein sequence analysis is also a large part of current phylogenic research and could accompany LS4 Biological Change: Unity and Diversity. Students may also consider the pros and cons of biotechnical applications. Investigation of techniques utilized could come from field trips to witness the use of these techniques in practice, lab exercises, virtual labs, simulation activities, interviews with professionals, etc. Molecular techniques could include: PCR, electrophoresis, restriction enzyme digestion of DNA, DNA sequencing, plasmid-based transformation, transfection, etc. These techniques are used in fields of medicine, agriculture, biomedical engineering, forensic science, etc.

Karyotyping

Lampbrush Chromosomes

In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, R&#252;ckert observed LBCs in shark egg cells and coined the ...

Polytene Chromosomes

Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in ...

Euchromatin

The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions ...

Heterochromatin

X and Y Chromosomes

Among mammals, the gender of an organism is determined by the sex chromosomes. Humans have two sex chromosomes, X and Y. Every human diploid cell has 22 ...

The Y Chromosome Determines Maleness

The Y chromosome is a sex chromosome&#160;found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human ...

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined ...

Investigate means by which karyotypes are utilized in diagnostic medicine.
EXPLANATION: Engineers incorporate growing scientific knowledge in order to increase benefits to humans and decrease cost and risks. Karyotyping technology and its use in medical diagnosis can complement the standards from LS3: Hereditary: Inheritance, and Variation of Traits, as the students are learning about chromosomal organization of genomic information that determines one's phenotype. Analyze a large set of karyotypes to identify common patterns. Identify variations from the most commonly observed patterns and correlate them with patient phenotypes to propose a cause and effect relationship, discussing limitations of correlative data interpretation.

BIO1.ETS2.2

Whole Body Regeneration

Regeneration is the process of restoring injured or lost tissues, organs, or&#160;body parts. While simpler organisms generally show greater ability to ...

Liver Regeneration

The liver is an important organ in vertebrates that plays an essential role in metabolism. It is also responsible for storing and redistributing nutrients ...

stem-cell-therapy-for-tissue-regeneration

Stem Cell Therapy for Tissue Regeneration

Stem cell therapy is a method used in regenerative medicine to repair and restore function to&#160;damaged tissues and organs. Stem cells have the ...

Introduction to Nuclear Reprogramming

Nuclear reprogramming is the process of switching gene expression of one cell type to that of another cell type, usually from a differentiated cell state ...

Methods of Nuclear Reprogramming

Nuclear reprogramming is a process of transforming one cell type into an unrelated cell type by epigenetic changes that alter the cell&#8217;s original ...

Cloning of Dolly the Sheep

The first successfully cloned mammal was Dolly, a sheep, born on 5th July 1996 at Roslin Institute, Scotland. The cloned sheep was named after the ...

Analyze scientific and ethical arguments to support the pros and cons of applications of a specific biotechnology technique such as stem cell usage, in vitro fertilization, or genetically modified organisms.
EXPLANATION: The utilization of new technologies in any field of science is dependent on both economic and social factors. In addition to evaluating these factors, scientists must also consider long-term consequences that may not be initially apparent. The emphasis should be on the construction of a rationale argument that supports a position on the use of an application with ethical and social impact. Students should begin to appreciate the differences in ethical values that exist, and recognize that discussion of these values is imperative as knowledge and technology continue to advance, even when resolutions of differences can be rare. After investigation of a specific biotechnology application, students can write a position paper and/or participate in a classroom debate.

BIO1.ETS2.3

RNAi for Gene Silencing and Discovery

Description

Transcript

Tags

More videos by Standards