Name: how viruses swap genes and spread
Uploaded: 2019-03-11T09:21:24.000Z
Duration: 57 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

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

From Molecules To Organisms: Structures And Processes

HS-LS1-8

Viral Recombination

Algumas células podem estar infetadas por duas cepas diferentes de um vírus ao mesmo tempo, causando uma confusão de ambas as sequências genéticas, em um processo denominado recombinação viral. Mais especificamente, depois que os vírus entram no citoplasma da célula, eles se desmontam e começam a replicar seus genomas. As regiões semelhantes de cada genoma podem emparelhar e trocar peças, reconectando as fitas.Alternativamente, os vírus podem trocar alguns de seus segmentos em um processo chamado rearranjo, em que novos vírus feitos dentro da célula pode ter uma mistura das cepas. Metade dos segmentos da cepa um e a outra metade da cepa dois. Esses vírus recém-formados, agora evoluíram de dois vírus originais, formando populações que podem continuar a mudar ao longo do tempo.

He, Ping, Guojun Wang, Yanning Mo, Qingxiong Yu, Xiong Xiao, Wenjuan Yang, Weifeng Zhao, et al. "Novos vírus da gripe triplo-recombinante em porcos, Guangxi, China." Micróbios e infecções emergentes 7 (16 de maio de 2018). <a href="https://doi.org/10.1038/s41426-018-0088-z" target="__blank">https://doi.org/10.1038/s41426-018-0088-z</a>.

recombinação viral

As células às vezes são infectadas por mais de um vírus ao mesmo tempo. Quando dois vírus se desmontam para expor os seus genomas para replicação na mesma célula, regiões semelhantes dos seus genomas podem unir-se e trocar sequências em um processo chamado recombinação. Alternativamente, vírus com genomas segmentados podem trocar segmentos em um processo chamado rearranjo.
 
 <h4>A Recombinação Viral Pode Criar Novas Doenças</h4>
 
 Algumas doenças podem infectar várias espécies. Por exemplo, os porcos podem ser infectados por alguns vírus de humanos e aves, além dos vírus que geralmente infectam porcos. Como os vírus podem recombinar quando co-infectam a mesma célula, os porcos podem agir como “recipientes de mistura” que recombinam vírus de outras espécies para criar novos vírus que às vezes podem infectar humanos. Este fenómeno preocupante representa uma via pela qual material infeccioso de outras espécies pode entrar na população humana. Doenças que passam de animais para humanos são conhecidas como zoonoses. Os humanos podem ser altamente susceptíveis a esses vírus por não terem histórico de exposição que teria criado imunidade.
 
 A influenza A é um óptimo exemplo da teoria do “recipiente de mistura” da doença viral. Investigações demonstraram que os vírus da gripe A em porcos, aves e humanos reassociaram-se dentro de hospedeiros suínos. Esses eventos produziram vírus “reassociados duplos” que continham genes de vírus de humanos e aves e vírus “reassociados triplos” que continham genes de vírus de humanos, aves e suínos. Nos Países Baixos, um vírus reassociado composto por genes da gripe humana e das aves foi transmitido de porcos para humanos.

Recombinação Viral

Às vezes, as células são infectadas por mais de um vírus ao mesmo tempo. Quando dois vírus se desmontam para expor seus genomas para replicação na mesma célula, ...

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Biology

Biologia

Genetics

Genética

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KEY TERMS AND CONCEPTS

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how viruses swap genes and spread

Viral gene swapping can happen when more than one virus infects the same cell. After the viruses break open and expose their genomes for replication, matching regions can pair up and exchange sequences. This process is called recombination. Viruses with segmented genomes can also swap whole segments, which is called reassortment.

These changes can help create new diseases. Some diseases can infect more than one species. Pigs can be infected by some human and bird viruses, along with the viruses that usually infect pigs. When different viruses co-infect the same pig cell, the pig can act as a mixing vessel and help produce new viruses that may infect humans.

This matters because diseases that move from animals to humans are called zoonoses. Humans can be highly susceptible to these viruses because we may not have previous exposure. Without that exposure, we would not have developed immunity. Influenza A is a clear example of the mixing vessel theory. Research has shown that pig, bird, and human influenza A viruses have reassorted inside pig hosts.

Some of those events produced double reassortant viruses with genes from human and bird viruses. Others produced triple-reassortant viruses with genes from human, bird, and pig viruses. In the Netherlands, a reassortant virus made from human and bird flu genes was passed from pigs to humans.

How Viruses Swap Genes and Spread

what are viruses?

How Viruses Infect Cells and Multiply

Viruses infect cells and make new copies by using a host cell’s own machinery. A virus is a tiny infectious particle with an RNA or DNA genome inside a protective protein coat. It cannot reproduce on its own, so it must enter a cell to make more viruses. After infection, the virus sheds its protein coat and uses the host cell to transcribe and translate its genetic material. The cell then assembles many new viral particles. In many cases, these new viruses rupture the host cell and kill it.

viral structure

How Virus Shapes Help Infection

Viruses have specific structures that help them infect host cells and trigger immune responses. Each virus has a core that contains either a DNA-based or RNA-based genome. That core is surrounded by a protective protein coat called the capsid. The capsid is made of smaller subunits called capsomeres. The capsid and the genome-containing core together are called the nucleocapsid. Viruses are often grouped by capsid design. Most viruses have either icosahedral or helical capsids, but some have...

lytic cycle of bacteriophages

How Phages Infect and Burst Bacteria

Bacteriophages, or phages, are viruses that infect bacteria. They have a distinctive head-tail shape. In the lytic cycle, a phage first attaches to the outside of a bacterial cell. Tail proteins bind to specific receptor proteins on the bacterium’s surface. After attachment, the phage tail injects its DNA genome into the bacterial cytoplasm. The phage then uses the bacterium’s cellular machinery to make proteins needed for replication and dispersal. When phage replication is complete, some of...

lysogenic cycle of bacteriophages

Prophage Integration in Bacteria

The lysogenic cycle shows how bacteriophages can infect bacteria without killing the host right away. In this cycle, the phage genome joins the bacterial genome. The integrated phage DNA is called a prophage, and the bacterium copies it each time it replicates. Some prophages can switch back into the lytic cycle. This change can happen after DNA damage or even without an obvious outside trigger. When the prophage is induced, the phage begins making new virus particles again. Prophages can...

retrovirus life cycles

How Retroviruses Replicate in Host Cells

Retroviruses replicate by copying their RNA genome into DNA inside a host cell. After entry, the viral enzyme reverse transcriptase makes a double-stranded DNA copy from the single-stranded RNA genome. The viral DNA is then carried into the nucleus and inserted into the host genome by integrase. Once integrated, the retroviral DNA is transcribed whenever the host genome is transcribed. This produces new viral RNA that can be copied and used again. The new RNA moves into the cytoplasm, where it...

viral recombination

Viral gene swapping can happen when more than one virus infects the same cell. After the viruses break open and expose their genomes for replication, matching regions can pair up and exchange sequences. This process is called recombination. Viruses with segmented genomes can also swap whole segments, which is called reassortment. These changes can help create new diseases. Some diseases can infect more than one species. Pigs can be infected by some human and bird viruses, along with the...

viral mutations

How Virus Mutations Drive Outbreaks

Virus mutations can change how quickly a virus evolves and spreads. A mutation is a change in the sequence of bases in DNA or RNA. Some mutations happen when the genome is copied. They are caused by errors made by polymerase enzymes, which replicate DNA or RNA. RNA viruses often change faster than DNA viruses because RNA polymerase does not proofread its work. That means RNA-based genomes, such as HIV, can gather mutations more quickly. Mutation and recombination give viruses the raw material...

key terms and concepts

Learn how viral recombination and reassortment happen when viruses infect the same cell, and how pigs can help new flu viruses spread to humans.

How Viruses Swap Genes and Spread | JoVE K12

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Nucleic Acids and Nucleotides

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Nucleic Acid Structure

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DNA Base Pairing

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The flow of genetic information in cells from DNA to mRNA to protein is described by the central dogma, which states that genes specify the sequence of ...

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Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA ...

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The central dogma explains the flow of genetic information from DNA nucleotides to the amino acid sequence of proteins.
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Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

RNA Structure

Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form ...

RNA Stability

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pre-mRNA Processing

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Types of RNA

Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs ...

DNA as a Genetic Template

What is Gene Expression?

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

Transcription

Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. ...

Translation

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Ribosomes

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tRNA Activation

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Termination of Translation

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Cell Diversity

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Cells of the Epidermis

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Lampbrush Chromosomes

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Neurons: The Axon

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Polytene Chromosomes

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Nervous Tissue: Neuron Types

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Euchromatin

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Heterochromatin

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chromatin-position-affects-gene-expression

Chromatin Position Affects Gene Expression

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Chromosome Structure

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HS-LS1-1

Characteristics of Life

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https://cloudfront.jove.com/files/media/science-education/science-education-thumbs/10647.jpg

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Taxonomy

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Phylogeny

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HS-LS1-2

Overview of Metabolism

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Regulation of Metabolism

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Positive and Negative Feedback Loops

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Negative and Positive Feedback

Homeostatic Imbalance

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pH Homeostasis

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homeostatic-imbalances-in-body-temperature

Homeostatic Imbalances in Body Temperature

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...

Regulation of Food Intake

The hypothalamus releases peptides influencing feeding behavior.
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HS-LS1-3

What is the Cell Cycle?

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Interphase

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The Cell Cycle Control System

Positive Regulator Molecules

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Cells Coordinate Growth and Proliferation

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Chromosome Duplication

Cohesins

Condensins

The Mitotic Spindle

Centrosome Duplication

Spindle Assembly

Attachment of Sister Chromatids

Forces Acting on Chromosomes

Separation of Sister Chromatids

The Spindle Assembly Checkpoint

Use a model to illustrate the role of the cell cycle and differentiation in producing and maintaining complex organisms. Emphasis is on conceptual understanding that mitosis passes on genetically identical materials via replication, not on the details of each phase in mitosis.

HS-LS1-4

How Viruses Swap Genes and Spread

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