Editing Simian immunodeficiency virus (section)

==Virology==
===Structure and genome===
The SIV virion is a spherical to pleomorphic glycoprotein envelope 110-120&nbsp;nm across enclosing a 110x50nm truncated cone or wedge-shaped (occasionally rod) capsid containing a [[dimer (chemistry)|dimer]]ic pair of [[positive-sense single-stranded RNA virus|positive-sense single-stranded RNA]] genomes.{{citation needed|date=November 2022}}

====Genome====
* coding regions

====Proteome====
{{Further|Structure and genome of HIV#Genome organization}}
* genes: ''env'', ''gag'', ''pol'', ''tat'', ''rev'', ''nef'', ''vpr'', ''vif'', ''vpu/vpx''
* Structural proteins (envelope): SU, TM(gag): MA, CA, NC
* Enzymes: RT, PR, IN
* Gene regulators: Tat, Rev
* Accessory proteins: Nef, Vpr, Vpx, Vif

===Tropism===
Differences in species specificity of SIV and related retroviruses may be partly explained by variants of the protein [[TRIM5-alpha|TRIM5α]] in humans and non-human primate species. This intracellular protein recognizes the [[capsid]] of various retroviruses and blocks their reproduction. Other proteins, such as [[APOBEC3G]]/[[APOBEC3F|3F]], which exerts antiretroviral immune activity, may also be important in restricting cross-species transmission.<ref>{{cite journal | vauthors = Heeney JL, Dalgleish AG, Weiss RA | title = Origins of HIV and the evolution of resistance to AIDS | journal = Science | volume = 313 | issue = 5786 | pages = 462–466 | date = July 2006 | pmid = 16873637 | doi = 10.1126/science.1123016 | s2cid = 27673160 | bibcode = 2006Sci...313..462H }}</ref>

===Replication===
* Attachment
* Penetration
* Uncoating
* Replication
** reverse transcription
  +ssRNA → -ssDNA → dsDNA → +ssRNA (viral genome)
                          → +ssmRNA → viral protein
:*integration
:*latency
:*cleavage
:*protein synthesis
:*Assembly
* Budding
* Maturation

===Quasispecies===
The speed and transcription inaccuracies of RNA viruses give rise to antigenically distinct varieties in a single host animal.  These ''[[viral quasispecies|quasispecies]]'' do not necessarily give rise to population-wide new organisms.  The rate of proliferation of quasispecies has significant implication for host immune control, and therefore virulence of the organism.{{citation needed|date=November 2022}}