Table of Contents
- 1 What is a gag gene?
- 2 What protein does gag code for?
- 3 What does the pol gene encode?
- 4 What three genes are present in all retroviruses?
- 5 Do humans have integrase?
- 6 What amino acid does gag code for?
- 7 What is hiv1 env?
- 8 What does rev protein do?
- 9 What is the function of the gag gene?
- 10 What is the function of the Gag protein in HIV 1?
- 11 Where does gene expression occur in viruses?
What is a gag gene?
The gag gene encodes the major structural polyprotein Gag and is all that is necessary and sufficient for the assembly non-infectious and immature viral-like particles. The viral protease is encoded by the pro gene and is responsible for facilitating the maturation of viral particles.
What protein does gag code for?
The three major proteins encoded within the retroviral genome: Gag, Pol, and Env. Gag is a polyprotein and is an acronym for Group Antigens (ag). Pol is the reverse transcriptase. Env in the envelope protein.
What are the two mechanisms used by retroviruses to produce a read through gag pol polyprotein?
Together, these results strongly indicate that the initiation of translation of the full-length Gag polyprotein can occur by three distinct mechanisms: first, ribosomal assembly, entry and scanning from the 5′-capped end of the genomic RNA; second, internal ribosome entry through the IRES element located within the 5′- …
What does the pol gene encode?
Pol gene products are critical for the synthesis and integration of viral DNA into the host genome and the generation of capsid proteins. Pol gene products include the HIV-1 reverse transcriptase, an integrase, and the late-phase protease.
What three genes are present in all retroviruses?
All retroviruses contain three major coding domains with information for virion proteins: gag, which directs the synthesis of internal virion proteins that form the matrix, the capsid, and the nucleoprotein structures; pol, which contains the information for the reverse transcriptase and integrase enzymes; and env.
How do retroviruses convert their RNA to DNA?
Retroviruses use reverse transcriptase to transform their single-stranded RNA into double-stranded DNA. It is DNA that stores the genome of human cells and cells from other higher life forms. Once transformed from RNA to DNA, the viral DNA can be integrated into the genome of the infected cells.
Do humans have integrase?
Human foamy virus (HFV), an agent harmless to humans, has an integrase similar to HIV IN and is therefore a model of HIV IN function; a 2010 crystal structure of the HFV integrase assembled on viral DNA ends has been determined.
What amino acid does gag code for?
glutamic acid
| Amino Acid | Coding DNA Strand Base Triplets Not Transcribed | Transfer RNA Anticodons Complementary To M-RNA Codons |
|---|---|---|
| cysteine | TGT, TGC | ACA, ACG |
| glutamic acid | GAA, GAG | CUU, CUC |
| glutamine | CAA, CAG | GUU, GUC |
| glycine | GGT, GGC, GGA, GGG | CCA, CCG, CCU, CCC |
Do retroviruses package reverse transcriptase?
Both the foamy retroviruses and the hepadnaviruses carry out reverse transcription in producer cells, rather than in newly infected cells (45, 99, 100). Thus, for these viruses, it is a dsDNA copy of the viral genome that is inside the virion and inside the capsid shell.
What is hiv1 env?
The Human Immunodeficiency Virus type 1 (HIV-1) env gene encodes the only surface-expressed viral protein Env, a glycoprotein of 160 kD (gp160), which is solely required for binding and entry into host cells.
What does rev protein do?
Rev is a transactivating protein that is essential to the regulation of HIV-1 (and other lentiviral) protein expression. A nuclear localization signal is encoded in the rev gene, which allows the Rev protein to be localized to the nucleus, where it is involved in the export of unspliced and incompletely spliced mRNAs.
Can retroviruses become dormant?
When integrated into a host genome, a retrovirus is hard to detect and can lay dormant for prolonged periods, having no discernible effect on the host. Retroviruses can be human pathogens, and cause many diseases, but have also proven to be invaluable tools when used by molecular biologists.
What is the function of the gag gene?
The gag gene encodes the major structural polyprotein Gag and is all that is necessary and sufficient for the assembly non-infectious and immature viral-like particles. The viral protease is encoded by the pro gene and is responsible for facilitating the maturation of viral particles.
What is the function of the Gag protein in HIV 1?
The Gag proteins of HIV-1, like those of other retroviruses, are necessary and sufficient for the assembly of virus-like particles. The roles played by HIV-1 Gag proteins during the life cycle are numerous and complex, involving not only assembly but also virion maturation after particle release and …
What is the structure of the gag/pol fusion protein in virions?
Little is known about the structure of the Gag/Pol fusion protein in the immature virion.
Where does gene expression occur in viruses?
In both cases, gene expression to produce viral proteins occurs in the cytoplasm where the protein synthetic machinery of the host cell may be utilized. The basic requirements for replication of viral genomes are the same as those for the infected cells.