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Chapter 20. oncogene, anti-oncogene and growth factor. The biochemistry and molecular biology department of CMU. Relationship of oncogene, anti-oncogene and growth factor. §1 Oncogene.
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Chapter 20 oncogene, anti-oncogene and growth factor The biochemistry and molecular biology department of CMU
Oncogenes are cellular genes that can trigger uncontrolled cell proliferation if their sequence is altered or their expression is incorrectly regulated.
A gene found in viruses or as part of the normal genome that is involved in triggering cancerous characteristics. • Control the cell growth and cell differentiation. • virus oncogene (v-onc) and cellular- oncogene (c-onc) or proto-oncogene
Virus- oncogene (v-onc) • Genes are in viruses that can cause tumors in vivo and transform the cell in vitro.
In 1910, Peyton Rous found the first retrovirus in a chickens filtrated sarcoma. Rous got the Nobel Prize in Physiology and Medicine in 1966.
Cellular Oncogene (c-onc) • Genes are in static or low-level expression state in normal cells under the normal situation and play an important role in maintaining the normal function of cells.
Category and major product of cellular oncogene 1. src family — tyrosine protein kinase 2. ras familiy — P21(GTPase activity) 3. myc familiy — intranuclear DNA binding protein 4. sis familiy — P28 (similar platelet derived growth factor) 5. myb familiy — intranuclear transcription factor
Product and Function of Proto-oncogene • Extracellular growth factors • Transmembrane growth factor receptors • Intracellular signal transduction proteins • Intranuclear transcription factors
Mechanisms of Oncogene Activation • Obtaining promoter or enhancer • Group translocation or chromosome rearrangements • Proto-oncogene amplification • Gene mutation
Tumor suppressor gene (anti-oncegene) • A gene whose protein products inhibit cell division, thereby preventing uncontrolled cell growth (cancer).
Coding the restrained protein relating to cell cycle control. • When tumor suppressive gene is deleted and mutated, there is an induced occurrence of tumors. • Rb gene and P53 gene.
Rb gene • Rb refers to retinoblastoma. • The major function of Rb gene is the regulation of cell cycle procession.
P53 gene • P53 gene encodes the protein which molecular weight is 53.
Biologic function of P53 protein • Suppressing cell cycle • Suppressing transformation function of some oncogenes • Monitoring cell DNA damage • Inducing the cell apoptosis
Growth Factor • A kind of signal molecules similar with hormones that are secreted by cells and promote cell proliferation and differentiation.
familiar human growth factor Factor Principal resource Primary function EGF Submaxillary gland, kidney, duodenal gland EPO HGF Placenta kidney IFN- γ Activated TH1 and NK cells IGF Placent, primarily liver, plasm NGF Neur, submaxillary gland PDGF Platelets,endothelial cells,placenta TGFα Tumor cell, transforming cell, placenta TGFβ Activated TH1 cells(T-helper) and natural killer(NK) cells VEGF Smooth muscle, tumor
Mechanism of action of growth factor Binding membrane receptor Binding intracellular receptor Tyrosine kinase activition Producing second messenger growth factor-receptorcompounds activation related gene Intracellular related protein phosphorylated Protein kinase activated genetic transcription Intranuclear transcription factor activation