Viruses replicate in the host cell and comprise either RNA or DNA genome enclosed by a protein capsid. The viruses comprise a genome composed of DNA viruses, while the viruses are composed of RNA re RNA viruses.
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On the basis of genome type, single-stranded RNA viruses can be classified into positive and negative sense RNA viruses. The positive sense RNA virus is also referred to as sense strand or plus-strand, while on the other hand, negative sense RNA is also referred to as antisense or minus strand.
The key difference between the negative and positive sense RNA virus is that the negative sense RNA virus comprises viral RNA, which is complementary to the viral mRNA, while the positive sense RNA virus comprises viral mRNA, which can be translated into proteins directly.
Positive Sense RNA Virus
- It is a type of virus containing a positive sense single-stranded RNA
- It is capable of operating as mRNA and can be directly translated into the protein in the host
- In the hosts, once the viral proteins are produced, it recruits RNA for the production of viral replication complexes
- The replication of the virus advances through the double-stranded intermediates of RNA
- Some examples are – echovirus, poliovirus,
Negative Sense RNA Virus
- It refers to the type of single-stranded RNA virus with genetic content being the antisense strand of the viral mRNA
- It comprises a genome that is complementary to the viral mRNA
- Consequently, the genome of the virus cannot translate readily into the viral proteins. As a result, the virion must be packed with RNA-dependant RNA polymerase enzyme, which helps in the transcription of the viral RNA
- Some examples are – the Ebola virus, influenza virus
Key Differences Between Positive and Negative Sense RNA Virus
The table below depicts the differences between Positive and Negative Sense RNA viruses.
| Comprises a single-stranded RNA as genetic content which directly works on mRNA | Comprises a single-stranded RNA as genetic content that generates a complementary sequence of mRNA |
| Positive sense RNA genome present | Negative sense RNA genome present |
| It happens through a double-stranded intermediate of RNA | It takes place with the help of RNA-dependant RNA polymerase |
| Not required | Before translation occurs, must be transcribed into positive sense RNA |
| It can be translated readily into proteins | It complements the mRNA |
| Sense strand | Antisense strand |
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