Regulation of Development

  1. Developmental potential?
    The ability of cells to develop into various cell types
  2. 4 Different levels of potential (i.e. types of stem cells)?
    Totipotent: can make all tissues and cell types AND extraembryonic tissues (zygote, blastomere in 4-cell embryo)

    Pluripotent: can make all cell types BUT NOT extraembryonic tissue (ICM, emb. stem cells, iPS)

    Multipotent: can make several cell types

    Unipotent: can make only one cell type
  3. Specification vs. determination? Which is reversible?
    Specification: cell acquires bias towards a particular fate from neutral environment (reversible)

    Determination: cell fate cannot be reversed from non-neutral environment
  4. 2 general mechanisms of fate specification?
    Autonomous specification: cell fate depends on determinants inherited from cell divisions (non-regulative)

    • Conditional specification: neighbor decide your fate (regulative, i.e. early during development the embryo can replace missing cells)
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  5. Which type of fate specification is mammalian development?
    conditional specification
  6. Genetic equivalence?
    When differentiating, genes are NOT lost...only the ones you need are expressed
  7. 5 mechanisms to regulate gene expression?
    • 1. transcription
    • 2. splicing
    • 3. export of processed mRNA
    • 4. translation/mRNA half-life
    • 5. post-translational modifications
  8. Patterns of gene expression in vivo?
    Spatial patterns (every cell type, tissue-specific, organ-specific, cell-type)

    Tempeoral patterns (constitutive, and modulated [i.e. inducible, repressible, rhythmic, circadian])
  9. What is context-dependent gene expression? 
    a gene that is re-expressed at a different time may have a similar, different, or opposite function form when it was initially expressed
  10. Definition of epigenetics?
    heritable states of gene expression without underlying alterations in DNA seq.
  11. 4 epigenetic mechanisms?
    imprinting - genes where only one allele is expressed and the other has been methylated (silenced)

    gene silenceing - repression of gene

    reprogramming- removing of epigenetic marks

    X-chromosome inactivation - regulation of X chromosome during dosage compensation
  12. X-chromosome inactivation? 
    Because girls have two X is inactivated (dosage compensation). However 25% of the inactivated X chromosome is transcriptionally active. 
Card Set
Regulation of Development
Med school