What type of nucleic acid do retroviruses contain

The ability of the retrovirus to bind to its target host cell using specific cell-surface receptors is given by the surface component SU of the env, while the ability of the retrovirus to enter the cell via membrane fusion is imparted by the membrane-anchored trans-membrane component TM. Thus, the env protein is what enables the retrovirus to be infectious.

Please refer to the figure, in it you see all the elements of a retroviral genome and how they interact to contribute to retroviral reverse transcription and integration. Retroviral genome. Reverse transcription occurs in the cytoplasm of host cell. Key: U3 — promoter region, U5 — recognition site for viral integrase; PBS — primer binding site; PP — polypurine section polypurine tract ; gag, pol, and env.

Colors mark complementary sequences. HIV replication depends on a complex, coordinated series of events where the virus integrates into the DNA of host cells. Human immunodeficiency virus HIV is a lentivirus a member of the retrovirus family that causes acquired immunodeficiency syndrome AIDS. AIDS is a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. HIV can infect dendritic cells DCs.

DCs are one of the first cells encountered by the virus during sexual transmission. They are currently thought to play an important role by transmitting HIV to T-cells when the virus is captured in the mucosa by DCs. HIV enters macrophages and T cells by the adsorption of glycoproteins on its surface to receptors on the target cell. This is followed by fusion of the viral envelope with the cell membrane and the release of the HIV capsid into the cell.

Together, the cDNA and its complement form a double-stranded viral DNA that is then transported into the cell nucleus. To actively produce the virus, certain cellular transcription factors need to be present. This means that those cells most likely to be killed by HIV are those currently fighting infection. During viral replication, the integrated DNA provirus is transcribed into mRNA, which is then spliced into smaller pieces.

These small pieces are exported from the nucleus into the cytoplasm, where they are translated into the regulatory proteins Tat which encourages new virus production and Rev.

As the newly produced Rev protein accumulates in the nucleus, it binds to viral mRNAs and allows unspliced RNAs to leave the nucleus, where they are otherwise retained until spliced. The full-length RNA is actually the virus genome; it binds to the Gag protein and is packaged into new virus particles. The final step of the viral cycle, assembly of new HIV-1 virions, begins at the plasma membrane of the host cell. The Env polyprotein goes through the endoplasmic reticulum and is transported to the Golgi complex.

These are transported to the plasma membrane of the host cell where gp41 anchors gp to the membrane of the infected cell. The Gag p55 and Gag-Pol p polyproteins also associate with the inner surface of the plasma membrane along with the HIV genomic RNA as the forming virion begins to bud from the host cell.

Maturation occurs either in the forming bud or in the immature virion after it buds from the host cell. This cleavage step can be inhibited by protease inhibitors. And so using the integrating ability of a retrovirus, you can actually take something that could ordinarily harm people and turn it into something that can be used as a therapeutic vehicle to make them better. David M. Bodine, Ph. Featured Content. Introduction to Genomics. Health Conditions Discover Plan Connect.

What Is a Retrovirus? Medically reviewed by Vincent J. Virus vs. They can be classified according to several factors, including: the type of genetic material they use DNA or RNA the method they use to replicate within the cell their shape or structural features Retroviruses are a type of virus in the viral family called Retroviridae.

How do they compare to other viruses? Which retroviruses can affect humans? How are retroviral infections treated? The bottom line. Read this next. Medically reviewed by Dr. Sirisha Yellayi, DO. Viral Diseases