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Chapter 3: Tumor Viruses Peyton Rous discovers a chicken sarcoma virus (1911)
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Rous sarcoma virus is discovered to transform infected cells in culture Retrovirus Renato Dulbecco (California IT) Harry Rubin/ An RSV-induced focus Howard Temin/ Transformation Howard Temin, 1975 Nobel Prize with David Baltimore
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Transformed cells forming foci.
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The continued presence of RSV is needed to maintain transformation
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Shope papillomavirus Viruses containing DNA molecules are also able to induce cancer SV40 virus Permissive host Polio vaccine (Sabin and Salk) contaminated with SV40 from 1955 to 1963
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Anchorage-independent growth Nude mice Tumor viruses induce multiple changes in cell phenotype including acquisition of tumorigenicity Transformation
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Tumor virus genomes persist in virus-transformed cells by becoming part of host-cell DNA Almost all cervical cancer found HPV genome
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The life cycle of an RNA tumor virus like RSV.
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A version of the src gene carried by RSV is also present in uninfected cells Structure of the RSV genome
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The construction of a src-specific DNA probe.
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RSV exploits a kidnapped cellular gene to transform cells Proto-oncogene
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The vertebrate genome carries a large group of protooncogenes
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Slowly transforming retroviruses activate protooncogenes by inserting their genomes adjacent to these cellular genes Some retroviruses naturally carry oncogenes Insertional mutagenesis ALV/ lack acquired oncogenes B-call lymphomas induced by ALV HTLV-I/ tax (transcription activator)
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Chapter 4: Cellular Oncogenes Can cancers be triggered by the activation of endogenous retroviruses? Transfection of DNA provides a strategy for detecting nonviral oncogenes Transfection
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Transformation of mouse cells by human tumor DNA
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Oncogenes discovered in human tumor cell lines are related to those carried by transforming retroviruses Homology between transfected and retroviral oncogenes. ×
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Amplification of the erbB2/HER2/neu oncogene in breast cancers Fluorescence in situ hybridization Kaplan-Meier plot
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Elevated expression of 17q genes together with overexpression of rebB2/HER2
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Nonrandom amplifications and deletions of chromosomal regions
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Proto-oncogenes can be activated by genetic changes affecting either protein expression or structure Cloning of transfected human oncogenes
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Localization of an oncogene-activating mutant transfection-focus assay
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Mutation responsible for H-ras oncogene activation Concentration of point mutations leading to activation of the K-ras oncogene
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Variations on a theme: the myc oncogene can arise via at least three additional distinct mechanisms N-myc amplification and neuroblastoma Gene myc MYC Protein Myc MYC
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Burkitt’s lymphoma incidence in Africa Chromosomal translocations in Burkitt’s lymphoma
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Translocations liberating an mRNA from miRNA inhibition
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A diverse array of structural changes in proteins can also lead to oncogene activation Deregulated firing of growth factor receptors
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Formation of the bcr-abl oncogene
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