Epigenetics

• What are the methods of epigenetic control?

  Methylation of DNA, Acetylation of DNA histones
• How do methyl groups affect gene activity?

  They can be added to DNA promoter to suppress transcription
• Which DNA base is commonly methylated to influence gene expression?

  Cytosine bases
• What is the effect of DNA methylation on gene transcription?

  It suppresses transcription by inhibiting the binding of RNA polymerase
• What factors can affect DNA methylation?

  Environmental, lifestyle, or age-related factors
• What can be added to lysine amino acids on histone proteins?

  Acetyl groups
• What charge does the R group of lysine have?

  Positively charged
• How do acetyl groups affect the interaction between histone proteins and DNA?

  They remove the bond between histone proteins and DNA, causing less tight wrapping
• What is the consequence of DNA being less tightly wrapped around histone proteins?

  RNA polymerase can bind more easily, activating gene expression
• What is the term used when acetyl groups are removed from lysine residues?

  Deacetylation
• What happens to lysine when acetyl groups are removed?

  Lysine returns to its positively charged state, inhibiting transcription
• How does the removal of acetyl groups affect gene expression?

  It stops the gene from being expressed by tightening the DNA around histones
• How do methyl groups suppress transcription?

  The methyl group binds to promoter, preventing RNA polymerase from transcribing DNA