Env (gene)
TLV/ENV coat polyprotein | |||||||||
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Identifiers | |||||||||
Symbol | TLV_coat | ||||||||
Pfam | PF00429 | ||||||||
InterPro | IPR018154 | ||||||||
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Env is a viral gene that encodes the protein forming the viral envelope.[1] The expression of the env gene enables retroviruses to target and attach to specific cell types, and to infiltrate the target cell membrane.[2]
Analysis of the structure and sequence of several different env genes suggests that Env proteins are
While there are significant differences in sequence of the env gene between retroviruses, the gene is always located downstream of gag, pro, and pol. The env mRNA must be spliced for expression.
The mature product of the env gene is the viral spike protein, which has two main parts: the surface protein (SU) and the transmembrane protein (TM). The
Physical structure
Oligomerization
The retroviral glycoproteins are oligomeric complexes that are composed of SU-TM
Post-translational modification
Env can be modified by the addition of mannose-rich oligosaccharides, a process that takes place in the rough endoplasmic reticulum and is carried out by the enzymes of the host cell. Cotranslational
In HIV
The env gene codes for the gp160 protein which forms a homotrimer, and is cleaved into gp120 and gp41 by the host cell
Env expression is regulated by the gene product of
env gp160; envelope glycoprotein | |||||||
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Identifiers | |||||||
Organism | |||||||
Symbol | env | ||||||
UniProt | P04578 | ||||||
Other data | |||||||
Chromosome | viral genome: 0.01 - 0.01 Mb | ||||||
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gp120
Exposed on the surface of the viral envelope, the
Since CD4 receptor binding is the most obvious step in HIV infection, gp120 was among the first targets of
gp41
The glycoprotein gp41 is non-
Env in MMTV
The Mouse Mammary Tumor Virus (MMTV) env gene codes for a polyprotein gp70 (P10259) that is cleaved to yield the surface (SU) and transmembrane (TM) Env products. Gp52 is the SU subunit in MMTV and gp36 is the TM subunit. Gp52 is a 52,000-dalton glycoprotein and gp36 is a 36,000-dalton glycoprotein.[15][16]
MMTV Env is of particular interest to researchers because of the discovery that it encodes an immunoreceptor tyrosine-based activation motif (I
Env in ASLV
Subgroup A
Avian Sarcoma and Leukosis Viruses (ASLV) have ten subgroups (A through J). The envelope glycoprotein of subgroup A is called EnvA and its env gene codes for precursor protein known as Pr95. This precursor is cleaved by host cell enzymes to yield the surface protein subunit, gp85, and the transmembrane protein subunit, gp37, which heterodimerize and then form a trimer. The virus cannot infect cells before the processing of the envelope precursor protein is completed.[17] For the virus to penetrate the cytosol of a host cell, a low pH is necessary.[18]
Env in MLV
The env gene of Murine Leukemia Virus (MLV) codes for the 71,000-dalton glycoprotein, gp71. This membrane receptor was isolated from Rauscher murine leukemia virus (R-MuLV).[19]
Env in mammalian evolution
The retroviral protein env has been captured multiple times during
See also
References
- ^ Gene+Products,+env at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
- ^ ISBN 978-0-87969-497-5.
- PMID 9707417.
- S2CID 31703688.
- PMID 2847170.
- PMID 1887590.
- PMID 22807678.
- PMID 1501294.
- PMID 8416385.
- PMID 2704072.
- S2CID 4367958.
- PMID 9420253.
- PMID 12970440.
- PMID 12637625.
- PMID 6252344.
- ^ PMID 15684322.
- PMID 10729148.
- PMID 15367609.
- S2CID 45192638.
- ^ Nova. 2016. Endogenous retroviruses. Retrieved from https://www.pbs.org/wgbh/nova/next/evolution/endogenous-retroviruses
- PMID 23938756.
External links
- Genes,+env at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
- env+Gene+Products,+Human+Immunodeficiency+Virus at the U.S. National Library of Medicine Medical Subject Headings (MeSH)