Genus Alpharetrovirus
|
|
|
|
Type Species |
Avian leukosis virus |
(ALV) |
Distinguishing Features
Virus particles assemble at the plasma membrane and exhibit a ‘C-type’ morphology. Proteins Mr are: MA ± 19 
103; p10 ± 10 103; CA ± 27 103; NC ± 12 103; PR ± 15 103; RT ± 68 103; IN ± 32 103; SU ± 85 103; TM ± 37 103. The genome is about 7.2 kb in size (one monomer); its organization is illustrated in Figure 2. There are no known additional genes other than gag, pro, pol, and env. The tRNA primer is tRNATrp. The LTR is about 350 nts long, of which the U3 region is 250, the R sequence 20 and the U5 region some 80 nts in size. The viruses have a widespread distribution and include both exogenous (vertical and horizontal transmission) and endogenous viruses of chickens and some other birds. ALV are classified into subgroups (e.g., -A, -J) by their distinct receptor usage. Distantly related endogenous sequences are found in birds and mammals. Virus infections are associated with malignancies and some other diseases such as wasting, and osteopetrosis. Many oncogene-containing members of the genus have been isolated.
List of Species Demarcation Criteria in the Genus
The list of species demarcation criteria is:
|
Differences in genome sequence, |
|
Differences in gene product sequences, |
|
Differences in natural host range, |
|
Different oncogenes that may be incorporated. |
For example, the avian leukosis viruses can be readily distinguished from Rous sarcoma virus because they lack oncogene sequences while encoding gag, pol and env. The replication defective Alpharetroviruses can be distinguished from Rous sarcoma virus by the variable deletion of portions of the gag, pol and env genes and the presence of a unique oncogene in each species. Rous sarcoma virus strains encode the src oncogene whereas Avian myeloblastosis virus, for example, encodes the myb oncogene. Host range, defined by SU interaction with a specific receptor, is generally used in defining strains within a species.
List of Species in the Genus
Official virus species names are in italics. Tentative virus species names, alternative names ( ), strains or serotypes are not italicized. Virus names, genome sequence accession numbers [ ], and assigned abbreviations ( ) are:
Species in the Genus
|
|
|
|
Avian leukosis virus |
|
(ALV) |
|
Avian leukosis virus - RSA |
[M37980] |
(ALV-A) |
|
Avian leukosis virus - HPRS103 |
[Z46390] |
(ALV-J) |
|
Oncogene containing viruses: |
|
Replication Competent: |
|
Rous sarcoma virus |
|
(RSV) |
|
Rous sarcoma virus (Prague C) |
[J02342] |
(RSV-Pr-C) |
|
Rous sarcoma virus (Schmidt-Ruppin B) |
[AF052428] |
(RSV-SR-B) |
|
Rous sarcoma virus (Schmidt-Ruppin D) |
[D10652] |
(RSV-SR-D) |
|
Replication Defective: |
|
Avian carcinoma Mill Hill virus 2 |
[K02082] |
(ACMHV-2) |
|
Avian myeloblastosis virus |
[J02013] |
(AMV) |
|
Avian myelocytomatosis virus 29 |
[J02019] |
(AMCV-29) |
|
Avian sarcoma virus CT10 |
[Y00302] |
(ASV-CT10) |
|
Fujinami sarcoma virus |
[J02194] |
(FuSV) |
|
UR2 sarcoma virus |
[M10455] |
(UR2SV) |
|
Y73 sarcoma virus |
[J02027] |
(Y73SV) |
Tentative Species in the Genus
None reported.
