Molecular Biology/Genetics USMLE Step 1 Practice Question
A 58-year-old man with newly diagnosed acute myeloid leukemia presents with fatigue, petechiae, and bleeding gums. Laboratory studies show WBC 87,000/μL and hemoglobin 7.2 g/dL. His leukemic cells are treated with an experimental histone deacetylase inhibitor. Chromatin analysis reveals increased acetylation of histone proteins and reactivation of transcription in previously silenced tumor suppressor gene regions. Which of the following best explains the mechanism underlying this therapeutic effect?
Answer choices
- AHistone acetylation loosens chromatin and promotes transcriptionCorrect answer
- BHistone acetylation condenses chromatin and represses transcription
- CTelomere shortening activates proto oncogenes
- DRestriction enzyme cleavage increases translation
- EDNA methylation always activates gene expression
- FHistone deacetylation increases DNA-histone binding affinity and silences gene expression
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