Tumor virus

Table 6. Some Tumor Viruses Which Cause Cellular Transformation...

Spom, M.B.. Roberts, A.B., Wakefield, L.M.. de Crombrugghe, B. (1987). Some recent advances in the chemistry and biology of transforming growth factor beta. J. Cell Biol. 105, 1039-1045. Tooze, J. (1973). The Molecular Biology of Tumor Viruses. Cold Spring Harbor Laboratory. Cold Spring Harbor, New York. 

This enzyme is associated with the virions of RNA tumor viruses such as the Rous sarcoma virus (RSV). The enzyme has remarkable enzymatic activity in that it can catalyze several seemingly diverse steps in the synthesis of double-stranded DNA from the single-stranded RNA viral genome. The enzyme uses a tRNA for tryp-tophan as a primer to make a copy of DNA that is complementary to the viral RNA. The resulting RNA-DNA hybrid is converted to a double-stranded DNA molecule by ribon-uclease (RNase)H and DNA-dependent DNA polymerase activities that are intrinsic to reverse transcriptase. 

Zhu Q, Gregg K, Lozano M, Liu J, Dudley JP (2000) CDP is a repressor of mouse mammary tumor virus expression in the mammary gland. J Virol 74(14) 6348-6357 Zweyer M, Riederer BM, Ochs RL, Fackelmayer FO, Kohwi-Shigematsu T, Bareggi R, Narducci P, Martelli AM (1997) Association of nuclear matrix proteins with granular and threaded nuclear bodies in cell lines undergoing apoptosis. Exp Cell Res 230(2) 325-336... 

Bhattacharjee RN, Banks GC, Trotter KW, Lee HL, Archer TK (2001) Histone HI phosphorylation by Cdk2 selectively modulates mouse mammary tumor virus transcription through chromatin remodeling. Mol Cell Biol 21(16) 5417-5425... 

The recent success of cloning the receptor for the mouse mammary tumor virus by screening a radiation hybrid (RH) panel (Ross et al., 2002), prompted us to use this approach to define the chromosomal localization of the M813 receptor. M813... 

Ross, S., Schofield, J., Farr, C. and Bucan, M. (2002) Mouse transferrin receptor 1 is the cell entry receptor for mouse mammary tumor virus. Proc. Natl. Acad. Sci, USA%%, 12386-12390. 

Tumor viruses carry activated versions of important cellular genes that regulate cell cycle and transcription. 

Vidarabine (adenine arabinoside, Vira-A) is an adenine nucleoside analogue containing arabinose in place of ri-bose. It is obtained from cultures of Streptomyces an-tibioticus and has activity against HSV-1, HSV-2, VZV, CMV, HBV, poxviruses, hepadnaviruses, rhabdoviruses, and certain RNA tumor viruses. 

Price, P.J. Mishra, N.K. (1980) The use of Fischer rat embryo cells as a screen for chemical carcinogens and the role of the nontransforming type C RNA tumor viruses in the assay. Adv. mod. environ. Toxicol.. 1. 213-239... 

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. 

Stephenson, J. R., ed. (1980) Molecular Biology ofRNA Tumor Viruses, Academic Press, New York... 

Reverse transcriptase RNA tumor viruses, e.g., avian myoblastosis virus 5 —> 3 DNA chain growth... 

Yang. R C.A.. and R. Wu BK Vims DNA Complete Nucleotide Sequence of a Human Tumor Virus. Stienrr. 206. 456-459 tl979t. 

Proopiomelanocortin ( ) Mammary tumor virus Pituitary Mammary gland Epidermis Fat body... 

RNA tumor viruses (retroviruses) that infect animal cells exhibit a different replication strategy. In their virions they carry an enzyme that uses the viral RNA as a template to synthesize a DNA copy (see chapters 26 and 27). This DNA becomes integrated into the host genome. Subsequently the viral RNA is transcribed from the integrated viral DNA using host cell RNA polymerase. 

Transformed cells sometimes, but not always, give rise to tumors when injected into an isogenic animal. There may be numerous reasons for the failure to produce tumors on all occasions. One of the best known reasons for lack of tumor production is immunological rejection. The transformed cell resulting from exposure to a tumor virus frequently displays viral antigens which are recognized as for-... 

Levine, A. J., The p53 protein and its interaction with the oncogene products of the small DNA tumor viruses. Virology 177 419-426, 1990. 

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