Question

Select the events that are a consequence of activating mutations in the ras gene. The ras proto-oncogene is converted into an oncogene. Specific transcription factors are activated by phosphorylation. The signal transduction cascade of the MAP kinases is repressed. Abnormally rapid cell growth and proliferation is induced. Malignant transformation of normal cells is inhibited.

Answer 1

Answer:

- The ras proto-oncogene is converted into an oncogene

- Specific transcription factors are activated by phosphorylation

- Abnormally rapid cell growth and proliferation is induced

Explanation:

The Ras genes are proto-oncogenes, i.e., genes with oncogenic potential that may induce cancer. These genes (Ras) encode GTPase proteins involved in transducing survival and growth signals. When Ras genes suffer mutations, the resulting Ras proteins may remain in an active state that prevents the hydrolysis of GTP, thereby the Ras pathway remains constitutively activated. In consequence, mutated Ras genes function as oncogenes by constitutively activating MAP kinases which in turn activate transcription factors that control the expression of target genes involved in critical cellular processes and whose expression is associated with cancer-specific events (eg., increased angiogenesis, increased cell proliferation, reduced apoptosis, etc).