A 4 year old boy is diagnosed with bilateral retinoblastoma. Genetic testing reveals a germline loss of one copy of the RB gene, and the tumor developed after somatic loss of the second copy in retinal cells. Which of the following best describes the normal function of the RB protein?

  1. A)DNA mismatch repair during replication
  2. B)Inhibition of the G1 to S transition by binding E2FGABARITO
  3. C)Activation of receptor tyrosine kinase signaling
  4. D)Repair of double stranded DNA breaks by homologous recombination
  5. E)Promotion of mitochondrial cytochrome c release

Explicação

RB is a tumor suppressor that restrains cell cycle progression by binding E2F and preventing transition from G1 into S phase. Loss of both RB alleles removes this brake and permits uncontrolled proliferation, the classic two hit mechanism in retinoblastoma. Ver explicação completa e trilha adaptativa →

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