Epigenetics

    Cards (43)

    • What do epigenetic mechanisms transduce?
      Inheritance of gene expression patterns
    • How do epigenetic mechanisms affect chromatin?
      They adapt chromatin without altering DNA sequence
    • What influences how DNA is packaged into chromosomes?
      Epigenetic modifications
    • How is DNA packaged in chromatin?
      Into nucleosomes with core histones
    • What are the core histones in nucleosomes?
      H2A, H2B, H3, and H4
    • What is the 'histone code'?
      Post-translational modifications of histones
    • What is the role of histone H1 in chromatin?
      Involves higher order packaging of DNA
    • What is chromatin?
      A complex of DNA and protein
    • What is heterochromatin?
      Compact chromatin that is inaccessible
    • How does euchromatin differ from heterochromatin?
      Euchromatin is loose and accessible
    • What is the significance of chromatin organization?
      It determines active and repressed gene states
    • What does methylation of DNA at CG dinucleotides do?
      Regulates gene expression
    • What is the role of DNA methyltransferases (DNMTs)?
      Catalyze methylation of cytosine
    • What happens to 5-methylcytosine (5mC)?
      It can be oxidized to 5-hydroxymethylcytosine
    • What is the function of thymine-DNA glycosylase (TDG)?
      Removes the carboxyl group from 5fC
    • How does DNA methylation silence genes?
      Methyl-binding domain proteins recruit repressive factors
    • What is the role of Polycomb and Trithorax group (PcG/TrxG)?
      Regulate gene expression during development
    • What is the significance of imprinting control regions (ICRs)?
      They establish and maintain DNA methylation imprints
    • What are the clinical features of Beckwith-Wiedemann Syndrome?
      Includes prenatal overgrowth and organomegaly
    • What molecular abnormalities are associated with Beckwith-Wiedemann Syndrome?
      Hypomethylation of ICR2 in 60% of cases
    • What are the clinical features of Silver-Russell Syndrome?
      Pre- and postnatal growth failure
    • What molecular abnormalities are associated with Silver-Russell Syndrome?
      Hypomethylation of ICR1 of chr11p15 in 60% of cases
    • What are the clinical features of Prader-Willi Syndrome?
      Severe hypotonia and obesity in childhood
    • What molecular abnormalities are associated with Prader-Willi Syndrome?
      Deletion of the PWS/AS region on paternal chr15
    • What are the clinical features of Angelman Syndrome?
      Severe mental retardation and speech impairment
    • What molecular abnormalities are associated with Angelman Syndrome?
      Deletion of the PWS/AS region on maternal chr15
    • What are the clinical features of imprinting disorders?
      • Growth abnormalities
      • Developmental delays
      • Increased tumor risk
    • What are the functions of imprinted genes?
      • Embryonic growth and placental function
      • Postnatal growth and adult metabolism
      • Behavior including social dominance and maternal care
    • What are the strengths and weaknesses of epigenetic therapies in cancer treatment?
      Strengths:
      • Target gene expression regulation
      • Potential to reverse aberrant epigenetic states

      Weaknesses:
      • Mode of action not fully understood
      • Risk of unintended consequences
    • What is the significance of the ENCODE project?
      • Maps regions of histone modification
      • Identifies regulatory regions in the genome
      • Provides insights into gene regulation
    • What are the roles of readers, writers, and erasers in epigenetics?
      • Readers: Recognize modifications
      • Writers: Add modifications
      • Erasers: Remove modifications
    • What is the relationship between DNA methylation and gene expression?
      • Methylation typically silences gene expression
      • Influences chromatin structure and accessibility
    • What are the implications of parental genome differences in imprinting?
      • Maternal and paternal imprints differ
      • Affect gene expression and development
    • What is the role of UBE3A in Angelman Syndrome?
      • UBE3A is involved in protein degradation
      • Its dysfunction leads to symptoms of Angelman Syndrome
    • What are the implications of the histone code in gene regulation?
      • Predicts regulatory regions
      • Influences gene expression outcomes
    • What are the roles of histone modifications in transcription regulation?
      • Modifications correlate with active/silent genes
      • Influence transcriptional elongation and replication
    • What is the significance of the 5mC to 5hmC conversion?
      • Represents a potential regulatory mechanism
      • Involves active demethylation processes
    • How does epigenetics contribute to cancer development?
      • Alters gene expression patterns
      • Disrupts cellular homeostasis
    • What are the common molecular abnormalities in imprinting disorders?
      • Uniparental disomy
      • Methylation changes
      • Chromosomal abnormalities
    • What is the significance of the methylation cycle in epigenetics?
      • Regulates gene expression
      • Involves dynamic changes during development
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