Name: rna virus replication strategies
Uploaded: 2025-06-12T09:30:23.000Z
Duration: 1 min 29 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Biology

BIO.4

BIO.4.a

Viruses with RNA Genomes

Les virus à ARN sont classés en deux catégories : sens positif, sens négatif ou double brin. Les virus à ARN de sens positif, tels que le bactériophage MS2, infectent E. coli via le pilus F, tandis que le poliovirus infecte principalement les humains via le récepteur du poliovirus sur les cellules. Les deux virus traduisent leur génome dès leur entrée dans l’hôte pour produire leurs composants structurels et enzymatiques. La grippe A est un virus à ARN simple brin pléomorphe, de sens négatif. Son génome d’ARN segmenté est divisé en huit brins hélicoïdaux enfermés dans une enveloppe lipidique dérivée de l’hôte. Lorsque deux virus de la grippe co-infectent la même cellule, leurs génomes segmentés peuvent se réassortir de manière aléatoire, produisant de nouvelles souches virales – un processus connu sous le nom de décalage antigénique. Les virus à ARN double brin, comme le rotavirus, se répliquent dans la nucléocapside, ce qui les protège de la détection immunitaire. Les rétrovirus, comme le VIH, utilisent la transcriptase inverse pour convertir l’ARN en ADN, qui s’intègre dans le génome de l’hôte pour la réplication. Les hépadnavirus, comme l’hépatite B, se répliquent par l’intermédiaire d’un ARN, formant un génome d’ADN partiellement double brin.

virus à génome arn

Les virus &#224; ARN sont class&#233;s en trois groupes selon la structure de leur g&#233;nome et leurs m&#233;canismes de r&#233;plication : ARN simple brin positif, ARN simple brin n&#233;gatif et ARN double brin. Cette classification d&#233;termine comment ces virus exploitent la machinerie cellulaire de l&#8217;h&#244;te pour la synth&#232;se des prot&#233;ines et la r&#233;plication. Certains virus &#224; ARN utilisent &#233;galement la transcription inverse dans leur cycle de vie, ce qui diversifie encore davantage leurs strat&#233;gies de r&#233;plication.
Virus &#224; ARN simple brin positif
Les virus &#224; ARN simple brin positif poss&#232;dent un g&#233;nome qui agit directement comme ARN messager (ARNm) d&#232;s l&#8217;infection, permettant la traduction imm&#233;diate des prot&#233;ines virales.
Le bact&#233;riophage MS2, un exemple bien connu, infecte Escherichia coli en s&#8217;attachant sp&#233;cifiquement aux pili F et en injectant son g&#233;nome ARN. L&#8217;ARN viral sert de matrice pour la traduction directe des prot&#233;ines virales, y compris l&#8217;ARN r&#233;plicase, essentielle &#224; l&#8217;amplification du g&#233;nome.
De m&#234;me, le poliovirus p&#233;n&#232;tre dans les cellules humaines et synth&#233;tise une polyprot&#233;ine de grande taille, qui est ensuite cliv&#233;e par des prot&#233;ases virales en composants structurels et enzymatiques n&#233;cessaires &#224; l&#8217;assemblage des virions.
Les coronavirus, tels que le SARS-CoV-2, emploient une strat&#233;gie plus complexe en produisant des ARN subg&#233;nomiques, permettant la traduction s&#233;lective de diverses prot&#233;ines virales. Ce m&#233;canisme favorise un cycle de r&#233;plication sophistiqu&#233; et contribue &#224; l&#8217;&#233;vasion des r&#233;ponses immunitaires de l&#8217;h&#244;te.
Virus &#224; ARN simple brin n&#233;gatif
Les virus &#224; ARN simple brin n&#233;gatif poss&#232;dent un g&#233;nome qui ne peut pas &#234;tre directement traduit ; il doit d&#8217;abord &#234;tre transcrit en ARNm par une ARN polym&#233;rase ARN-d&#233;pendante virale.
Le virus de la rage utilise ce m&#233;canisme, sa polym&#233;rase g&#233;n&#233;rant des ARNm traduits ensuite en prot&#233;ines virales n&#233;cessaires &#224; la r&#233;plication et &#224; l&#8217;assemblage des virions.
Le virus de la grippe, un autre virus &#224; ARN n&#233;gatif, poss&#232;de un g&#233;nome segment&#233; qui permet le r&#233;assortiment g&#233;n&#233;tique. Lorsque diff&#233;rentes souches infectent une m&#234;me cellule h&#244;te, elles peuvent &#233;changer des segments g&#233;nomiques, provoquant un changement antig&#233;nique &#8212; un processus &#224; l&#8217;origine de nouvelles souches grippales pand&#233;miques. En revanche, la d&#233;rive antig&#233;nique r&#233;sulte de l&#8217;accumulation progressive de mutations, entra&#238;nant les variations saisonni&#232;res de la grippe.
Virus &#224; ARN double brin
Les virus &#224; ARN double brin, comme le rotavirus de la famille des Reoviridae, se r&#233;pliquent &#224; l&#8217;int&#233;rieur de la nucl&#233;ocapside virale. Cette protection isole l&#8217;ARN viral des m&#233;canismes de d&#233;tection de l&#8217;h&#244;te, facilitant l&#8217;&#233;vasion immunitaire.
Lors de la r&#233;plication, le virus transcrit des brins d&#8217;ARN positif &#224; partir de son g&#233;nome double brin, lesquels servent de matrice pour la synth&#232;se prot&#233;ique et la r&#233;plication du g&#233;nome. Cette strat&#233;gie de r&#233;plication contr&#244;l&#233;e permet une propagation efficace du virus tout en minimisant la r&#233;ponse immunitaire de l&#8217;h&#244;te.
Virus &#224; transcription inverse
Certains virus &#224; ARN utilisent la transcription inverse pour se r&#233;pliquer, convertissant leur ARN en ADN au cours de leur cycle de vie.
Les r&#233;trovirus, tels que le VIH, utilisent la transcriptase inverse pour synth&#233;tiser un ADN compl&#233;mentaire (ADNc) &#224; partir de leur g&#233;nome ARN. Cet ADNc s&#8217;int&#232;gre ensuite dans le g&#233;nome de l&#8217;h&#244;te, permettant une infection persistante et une latence &#224; vie.
En revanche, les h&#233;padnavirus, tels que le virus de l&#8217;h&#233;patite B (VHB), adoptent une strat&#233;gie de r&#233;plication unique. Bien que le VHB soit un virus &#224; ADN, il utilise la transcription inverse pour convertir un interm&#233;diaire ARN en un g&#233;nome ADN partiellement double brin. Ce m&#233;canisme le distingue des virus &#224; ADN classiques, illustrant une voie de r&#233;plication distincte.

Virus à génome ARN

Les virus &#224; ARN sont class&#233;s en trois groupes selon la structure de leur g&#233;nome et leurs m&#233;canismes de r&#233;plication : ARN simple ...

Education

Enseignement

JoVE Core

Microbiology

Microbiologie

Unit

Unité

Viruses

Virus

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

rna virus replication strategies

RNA viruses use several replication strategies based on their genome type. They are grouped as positive-strand, negative-strand, or double-stranded RNA viruses. Some RNA viruses also use reverse transcription, which adds another layer to how they copy their genetic material.

Positive-strand RNA viruses have genomes that can act like messenger RNA, or mRNA, as soon as they enter a cell. This lets the virus begin making proteins right away. Bacteriophage MS2 infects Escherichia coli by attaching to F pili and injecting its RNA genome. That RNA is then translated to make viral proteins, including RNA replicase, which helps copy the genome.

Poliovirus uses a similar direct-use strategy in human cells. It makes one large polyprotein, which viral proteases later cut into structural and enzymatic parts needed to build new virions. Coronaviruses, such as SARS-CoV-2, take a more complex route. They produce subgenomic RNAs so different viral proteins can be translated selectively, which supports their replication cycle and can help them evade host immune responses.

Negative-strand RNA viruses cannot be translated directly. They must first use a viral RNA-dependent RNA polymerase to make mRNA. Rabies virus follows this pattern, and the mRNAs it makes are then translated into proteins needed for replication and assembly.

Influenza virus is another negative-strand RNA virus, but it has a segmented genome. If two influenza strains infect the same cell, they can exchange genome segments. This reassortment can cause antigenic shift, which can lead to new strains with pandemic potential. Antigenic drift is different. It comes from the gradual buildup of mutations and leads to seasonal influenza changes.

Double-stranded RNA viruses, such as rotavirus from the Reoviridae family, replicate inside the viral nucleocapsid. This keeps the viral RNA hidden from host immune detection. During replication, the virus makes positive-strand RNA from the double-stranded genome, and that RNA serves as a template for protein synthesis and genome copying.

Some RNA viruses also rely on reverse transcription. Retroviruses, such as HIV, use reverse transcriptase to make complementary DNA, or cDNA, from their RNA genome. That cDNA integrates into the host genome, which can support persistent infection and lifelong latency. Hepadnaviruses, such as hepatitis B virus, use a different reverse-transcription pathway. Although HBV is a DNA virus, it converts an RNA intermediate into a partially double-stranded DNA genome.

RNA Virus Replication Strategies

introduction to virus

Virus Structure, Entry, and Replication

Viruses are biological entities that rely on host cells to make more copies of themselves. They do not have cells or their own metabolism, but they can show signs of life when they infect a host. Their basic structure includes a nucleic acid core, made of either DNA or RNA, surrounded by a protein coat called a capsid. Viruses are classified by the type of nucleic acid they contain and by their structure. Some viruses also have a lipid envelope that comes from the host cell membrane. Enveloped...

size and structure of viral genomes

How Viral Genomes Replicate

Viral genomes can be DNA or RNA, and their structure shapes how they replicate inside host cells. They may be linear or circular. They can also be single-stranded or double-stranded. These differences affect how a virus makes copies of itself and how it interacts with the host. RNA viruses usually have smaller genomes than DNA viruses. That smaller size is linked to high mutation rates and fast evolution. RNA virus polymerases often lack proofreading, so mistakes are more common. This helps...

viral replication: lytic cycle

T4 Phage Infection of E. coli

T4 phage infection of E. coli follows a lytic cycle that lets the virus make many copies fast. Bacteriophages, or phages, are viruses that infect bacteria, and T-even phages such as T4 are known for this well-studied process. The cycle ends with the destruction of the bacterial host. The first step is attachment to the E. coli cell surface. Tail fibers on the phage bind to receptor molecules on the bacterial outer membrane, which helps the virus find the correct host. After binding, the...

viral replication: lysogenic cycle

Prophage Integration in Bacterial Cells

The lysogenic cycle shows how a bacteriophage can stay inside a bacterial cell without killing it right away. Temperate phages, such as bacteriophage lambda (λ), use this strategy to persist in Escherichia coli while the host cell remains alive. After attachment to the bacterial surface, the phage injects its genetic material into the cytoplasm. The linear phage genome then circularizes, which helps protect it from host nucleases. Next, phage-encoded integrase carries out recombination that...

dna bacteriophages

How DNA Phages Replicate in Bacteria

DNA bacteriophages are viruses that infect bacteria and use bacterial cell machinery to make more copies of themselves. They carry either single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA), and each group uses a different replication strategy. Their life cycles also shape how they interact with hosts and how scientists use them in biotechnology and medicine. Some ssDNA phages keep their genomes very small and compact. The icosahedral phage ΦX174 shows this clearly because it uses...

viruses of archaea

Archaeal Virus Shapes and Extreme Survival

Archaeal viruses infect archaea that live in extreme places such as acidic hot springs and hydrothermal vents. These hosts often belong to the phyla Euryarchaeota and Crenarchaeota. The viruses help shape host evolution and gene transfer, which adds genetic diversity to microbial communities in harsh environments. Most archaeal viruses carry double-stranded DNA, or dsDNA, genomes. Some have single-stranded DNA, and some have RNA genomes. Their virions, or complete virus particles, show unusual...

viruses with rna genomes

RNA viruses use several replication strategies based on their genome type. They are grouped as positive-strand, negative-strand, or double-stranded RNA viruses. Some RNA viruses also use reverse transcription, which adds another layer to how they copy their genetic material. Positive-strand RNA viruses have genomes that can act like messenger RNA, or mRNA, as soon as they enter a cell. This lets the virus begin making proteins right away. Bacteriophage MS2 infects Escherichia coli by attaching...

the antiviral system of bacteria and archaea: crispr

the-antiviral-system-of-bacteria-and-archaea-crispr

How CRISPR Remembers Viral Infections

CRISPR is an adaptive immune system in bacteria and archaea that helps protect cells from viral infection. It works by identifying foreign genetic material, remembering it, and stopping the same invader later. In many cases, the main targets are bacteriophages, which are viruses that infect bacteria. The first defense step begins during an initial infection. Cas proteins, which are CRISPR-associated proteins, detect foreign DNA by looking for specific sequences called Protospacer Adjacent...

crispr/cas9 genome editing

CRISPR-Cas9 and DNA Repair in Cells

CRISPR-Cas9 uses a bacterial defense system to change DNA in cells. The CRISPR-Cas system first evolved in prokaryotes to protect bacteria from invading genetic material such as viruses and plasmids. Scientists later adapted it into a genome-editing tool for plants, animals, and humans. The key enzyme is Cas9, a DNA-cutting protein called an endonuclease from Streptococcus pyogenes. In the lab, a synthetic single guide RNA, or sgRNA, directs Cas9 to a chosen DNA site. The sgRNA matches the...

subviral agents

Viroids, Prions, and Satellite Viruses

Viroids, prions, and satellites are subviral agents that can cause infection even though they are not complete viruses. They resemble viruses in spread and disease, but each lacks one or more key viral parts, such as a capsid or the machinery needed for replication. Viroids are the simplest of these agents. They are circular, single-stranded RNA molecules with no protein coat. Viroids infect plants only and depend on host cell machinery to copy themselves. Host RNA polymerase replicates them...

key terms and concepts

Explore how RNA viruses replicate through positive-strand, negative-strand, double-stranded, and reverse-transcribing strategies, with examples like poliovirus, influenza, and HIV.

RNA Virus Replication Strategies | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Alabama Course of Study Science

9-12

Unity and Diversity

9-12.B.4.13.a

Introduction to Virus

Viruses are unique biological entities that blur the boundary between living and non-living systems. Although they lack cellular structure and metabolic ...

Size and Structure of Viral Genomes

Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. ...

Viral Replication: Lytic Cycle

Bacteriophages, or phages, are viruses that specifically infect bacteria. Among them, T-even bacteriophages, such as T4, exhibit a well-characterized ...

Viral Replication: Lysogenic Cycle

The lysogenic cycle is a crucial viral replication strategy that allows bacteriophages to persist within host cells without immediately destroying them. ...

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for ...

Viruses of Archaea

Archaeal viruses play a crucial role in the ecosystems of extremophilic archaea, particularly those belonging to the phyla Euryarchaeota and ...

RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. ...

The Antiviral System of Bacteria and Archaea: CRISPR

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats is a adaptive immune system found in bacteria and archaea that protects ...

CRISPR/Cas9 Genome Editing

The CRISPR-Cas system serves as a bacterial defense mechanism against invading genetic elements such as viruses and plasmids, forming the foundation for ...

Subviral Agents

Subviral agents are infectious entities that resemble viruses but lack one or more viral components, such as a capsid or essential replication machinery. ...

The student will investigate and understand that bacteria and viruses have an effect on living systems. Key ideas include  viruses depend on a host for metabolic processes;

Binary Fission

Binary fission is the primary mode of asexual reproduction in prokaryotes, such as bacteria. It results in the production of two genetically identical ...

Generation Time

Bacterial generation time, the period required for a bacterial population to double during its exponential growth phase, serves as a critical measure of ...

Bacterial Growth Curve

The bacterial growth curve is a fundamental concept in microbiology that describes the dynamics of bacterial population growth in a closed system with ...

microbial-growth-measurement-direct-methods

Microbial Growth Measurement: Direct Methods

Direct methods for measuring microbial populations in a culture are essential tools in microbiology, providing quantitative data for various applications. ...

microbial-growth-measurement-indirect-methods

Microbial Growth Measurement: Indirect Methods

Estimating microbial growth is essential for understanding population dynamics and environmental adaptations. Indirect methods provide valuable insights ...

Microbial Growth Media

Microbial growth media are essential tools in microbiology, providing the nutrients and conditions necessary to cultivate and study microorganisms. These ...

Need for Obtaining Pure Cultures

Pure cultures, defined as the growth of a single microorganism species isolated from mixed populations, are fundamental tools in microbiological research ...

techniques-for-isolation-of-pure-cultures

Techniques for Isolation of Pure Cultures

Microorganisms are routinely cultured in the laboratory using various techniques to isolate, grow, and quantify them for further study. These methods rely ...

Factors Influencing Microbial Growth: pH

Microorganisms are classified as acidophiles, neutrophiles, or alkaliphiles based on their pH growth preferences, reflecting their adaptations to specific ...

factors-influencing-microbial-growth-temperature

Factors Influencing Microbial Growth: Temperature

Microorganisms display remarkable adaptations, enabling them to thrive in diverse ecological niches across a wide range of temperatures. Temperature ...

factors-influencing-microbial-growth-osmolarity

Factors Influencing Microbial Growth: Osmolarity

Osmolarity is the measure of solute concentration in a solution. It plays a critical role in determining water availability for organisms. Water moves ...

Oxygen Requirements and Growth Patterns

Microorganisms exhibit diverse oxygen requirements and growth patterns driven by their metabolic strategies and environmental adaptations. Oxygen, while ...

Biofilms

Biofilms are complex communities of microorganisms encased in a self-produced extracellular polysaccharide matrix attached to surfaces. These microbial ...

The student will investigate and understand that bacteria and viruses have an effect on living systems. Key ideas include the modes of reproduction/replication can be compared

BIO.4.b

Prokaryotic vs. Eukaryotic Cells

Prokaryotic and eukaryotic cells represent two fundamental types of cellular organization, differing significantly in structure, complexity, and function. ...

Microbial Morphologies 

Bacterial and archaeal cells exhibit remarkable diversity in shape and structure, critical in their adaptability and functionality. Among bacteria, the ...

Bacterial Cell Wall 

The bacterial cell wall is an essential structural component that encases the plasma membrane, preserving cellular integrity, determining shape, and ...

Archaeal Cell Wall

Archaeal cell walls are structurally and compositionally distinct from their bacterial counterparts, lacking the characteristic peptidoglycan layer found ...

Peptidoglycan Synthesis

Structure of PeptidoglycanPeptidoglycan is a vital structural component of the bacterial cell wall, providing mechanical strength and shape to the cell. ...

Plasma Membrane in Bacteria and Archaea

The plasma membrane is an essential cellular structure responsible for maintaining cellular integrity and regulating the selective transport of molecules. ...

Outer Layers of the Cell Envelope

The outermost layers of prokaryotic cells play a critical role in their survival, virulence, and interaction with the environment. These layers, often ...

Flagella and Motility in Bacteria

Flagella are specialized, thread-like structures that extend from a bacteria's cell envelope. They play a crucial role in motility and chemotaxis. Their ...

Fimbriae, Pili, and Axial Filaments

Fimbriae and pili are specialized bacterial surface structures that play pivotal roles in adhesion, genetic exchange, and motility. Composed primarily of ...

Cell Inclusions

Prokaryotic cells possess a variety of inclusions that play crucial roles in nutrient storage, metabolic processes, and environmental adaptation. These ...

Endospores and Sporulation

Endospores are specialized, dormant cells primarily formed by Gram-positive bacteria, including Bacillus and Clostridium, enabling survival under extreme ...

Nucleoid

The nucleoid represents a structurally and functionally distinct region within prokaryotic cells, where the cell's DNA and associated proteins are housed. ...

Surface Appendages of Archaea

Archaeal surface appendages are highly specialized structures essential for environmental adaptation, encompassing roles in adhesion, biofilm formation, ...

The student will investigate and understand that bacteria and viruses have an effect on living systems. Key ideas include  the structures and functions can be compared

BIO.4.c

Types of Microorganisms

Microorganisms are a diverse group of microscopic entities broadly categorized into cellular and acellular types based on their structural organization. ...

environmental-applications-of-microorganisms

Environmental Applications of Microorganisms

Microorganisms play a pivotal role in maintaining ecosystem balance by recycling essential elements such as carbon, nitrogen, and phosphorus, as well as ...

community-dna-extraction-from-bacterial-colonies

Community DNA Extraction from Bacterial Colonies

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Author: Luisa Ikner
Traditional methods of analysis ...

detecting-environmental-microorganisms-with-polymerase-chain-reaction

Detecting Environmental Microorganisms with the Polymerase Chain Reaction and Gel Electrophoresis

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Bradley Schmitz
Polymerase chain reaction (PCR) is ...

rna-analysis-of-environmental-samples-using-rt-pcr

RNA Analysis of Environmental Samples Using RT-PCR

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Author: Bradley Schmitz
Reverse ...

quantifying-environmental-microorganisms-and-viruses-using-qpcr

Quantifying Environmental Microorganisms and Viruses Using qPCR

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Author: Bradley Schmitz
Quantitative polymerase ...

water-quality-analysis-via-indicator-organisms

Water Quality Analysis via Indicator Organisms

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba -The University of Arizona
Demonstrating Author: Luisa Ikner
Water quality analysis monitors ...

isolation-of-fecal-bacteria-from-water-samples-by-filtration

Isolation of Fecal Bacteria from Water Samples by Filtration

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Author: Luisa Ikner
The quality of water destined ...

detection-of-bacteriophages-in-environmental-samples

Detection of Bacteriophages in Environmental Samples

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Author: Alex Wassimi
Viruses are a unique group of ...

culturing-and-enumerating-bacteria-from-soil-samples

Culturing and Enumerating Bacteria from Soil Samples

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Authors: Bradley Schmitz and Luisa Ikner
Surface ...

bacterial-growth-curve-analysis-and-its-environmental-applications

Bacterial Growth Curve Analysis and its Environmental Applications

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - The University of Arizona
Demonstrating Author: Luisa Ikner
Bacteria are among the most ...

The student will investigate and understand that bacteria and viruses have an effect on living systems. Key ideas include  bacteria and viruses have a role in other organisms and the environment; and

BIO.4.d

History of Microbiology

Microbiology, a scientific field dedicated to the study of microorganisms, has undergone profound development since its inception in the 17th century. Its ...

Infection

When a pathogen enters the body and reproduces, it can cause an infection, damage body cells, and cause illness symptoms that eventually lead to disease. ...

Defense Mechanism Against Infection

Natural flora, body system defenses, and inflammation are natural barriers of the body against infectious agents regardless of previous exposure. Normal ...

The student will investigate and understand that bacteria and viruses have an effect on living systems. Key ideas include  the germ theory of infectious disease is supported by evidence.

BIO.4.e

RNA Virus Replication Strategies

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