Avian oncogenic virus

Frykberg, L., S. Palmieri, H. Beug, T. Graf, M.J. Hayman, and B. Vennstrom, Transforming capacities of avian erythroblastosis virus mutants deleted in the erbA or erbB oncogenes. Cell, 1983. 32(1) 227-38. 

Vennstrom B, Bishop JM. Isolation and characterization of chicken DNA homologous to the two putative oncogenes of avian erythroblastosis virus. Cell 1982 28 135-143. 

Retroviruses have featured prominently in recent advances in the molecular understanding of cancer. Most retroviruses do not kill their host cells but remain integrated in the cellular DNA, replicating when the cell divides. Some retroviruses, classified as RNA tumor viruses, contain an oncogene that can cause the cell to grow abnormally (see Fig. 12-47). The first retrovirus of this type to be studied was the Rous sarcoma virus (also called avian sarcoma virus Fig. 26-31), named for F. Peyton Rous, who studied chicken tumors now known to be caused by this virus. Since the initial discovery of oncogenes by Flarold Varmus and Michael Bishop, many dozens of such genes have been found in retroviruses. 

In fact, when the primary structure of the first steroid receptor, the human glucocorticoid receptor [79] was deduced from the nucleotide sequence the homology of this central region with the product of the v-erb-A oncogene of the avian erythroblastosis virus immediately became conspicuous [80]. This similarity subsequently led to the identification of c-erb-A, the cellular counterpart of v-erb-A, as the gene for a thyroid hormone receptor [92,93]. The kinship amongst these sequences has also greatly helped to identify cDNA clones for other steroid hormone receptors. 

Crk is a protooncogene, related to v-crk, the oncogene of the avian sarcoma virus CTIO. Crk is the abbreviation of T regulator of ase. Although, Crk induces tyrosine phosphorylation, it is not a tyrosine kinase. It is actually a linker, containing SH2 and SH3 domains which links up with tyrosine kinases. 

REL is a family of genes, encoding transcription factors of the kH family, v-rel is the oncogene of an avian reticuloendothelial virus. Rel encodes proteins which form homo-and heterodimers that bind to genes, which are also adressed by NF-icB. 

The c-myc gene is the proto-oncogene of avian myelocytoma virus. It binds to DNA and is involved in transcription regulation. The gene product, p62, is located in the nucleus of transformed cells, and levels of c-myc correlate with the rate of cell division. The c-myc protein is essential for DNA replication and enhances mRNA transcription. Activation of the c-myc gene is associated with B- and T-ceH lymphoma, sarcomas, and endotheliomas. In leukemias and lymphomas, increased c-myc expression may be due to amplification or chromosomal translocation of the gene. In acute T-celi leukemias, there is an (8 14) (q24 qll) translocation that... 

Neckameyer, W.S. Wang, L.H. Nucleotide sequence of avian sarcoma virus UR2 and comparison of its transforming gene with other members of the tyrosine protein kinase oncogene family. J. Virol., 53, 879-884 (1985)... 

Debuire, B. Henry, C. Bernissa, M. Biserte, G. Claverie, J.M. Saule, S. Martin, R Stehelin, D. Sequencing the erbA gene of avian erythroblastosis virus reveals a new type of oncogene. Science, 224, 1456-1459 (1984)... 

Marx, M. Eychene, A. Laugier, D. Bechade, C. Crisanti, P. Dezelee, R Pessac, B. Calothy, G. A novel oncogene related to c-mil is transduced in chicken neuroretina cells induced to proliferate by infection with an avian lymphomatosis virus. EMBO J., 7, 3369-3373 (1988)... 

Smith, R.E. and Moscovid, C. 1%9. The oncogenic effects of nontransforming viruses from avian myeloblastosis virus. Cancer Res. 29, 1356 1366. 

RSV is rather an unusual transforming retrovirus in possessing the complete set of genes for replication, and also an oncogene. Most of the avian transforming viruses lack at least one or part of one of the other genes necessary for replication (see Fig. 11.4). 

Most retroviral genomes encode a single oncogene, but avian leukaemia virus E26 has both myb and ets and is able to induce two types of tumour, namely myeloblastosis and erythroblastosis (Watsoa McWilliams Papas, 1988). 

Two avian oncogenes that encode protein kinases are cytoplasmic proteins not associated with membranes rel and mil rel occurs in avian reticuloen-dotheliosis virus (REV-T), which has been described as the most virulent of all retroviruses, causing a rapidly fatal lymphoma with a latent period of one to two weeks and a mortality approaching 100% (Moore Bose, 1989). A modified form of REV has... 

---