A. Normally involved in cell cycle proliferation
B. Produces tumor
C. Proto-oncogenes on mutation causes cancer.
D. A and C both
Proto-oncogenes are important regulatory genes of the cells. Exposure of target cells to PDGF can result in rapid (minutes to 1–2 h) activation of the expression of the genes encoding certain cellular proto-oncogenes (eg, MYC and FOS) that participate in stimulation of mitosis via effects on the cell cycle.
Point Mutation of Proto-oncogene: The ras gene produces a protein termed P21 (Mol. wt. 21,000) related to the GTPase, that suppresses the activity of adenyl cyclase. Adenyl cyclase has a key role in the cellular response to hormones. C-ras oncogene product is a mutated version of P21. So, GTPase activity is decreased leading to continuous activity of adenyl cyclase.