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Posts Tagged ‘target sites on chromatin’

Reprogramming Cell Fate

 

Reporter: Larry H.Bernstein, MD, FCAP

Kathy Liszewski: reporting Gordon Conference “Reprogramming Cell Fate” meeting
M. Azim Surani, Ph.D., Univ Cambridge
Source unknown: June 21, 2012;32(11)
They report two critical steps both of which are needed for exploring epigenetic reprogramming.  While females have two X chromosomes ,
  • the inactivation of one is necessary for cell differentiation.
  • Only after epigenetic reprogramming of the X chromosome can pluripotency be acquired.

Pluripotent stem cells can generate – any fetal or adult cell type but

    • don’t develop into a complete organism.
Pioneer transcription factors take the lead in – facilitating cellular reprogramming – and responses to environmental cues.
Multicellular organisms consist of
  • functionally distinct cellular types
  • produced by differential activation of gene expression.
They seek out and bind specific regulatory sequences in DNA, even though DNA is coated with and condensed into a thick fiber of chromatin.
The pioneer factor, discovered by Prof. KS Zaret at UPenn SOM in 1996, endows the competence for gene activity,
  • being among the first transcription factors to
  • engage and pry open the target sites in chromatin.
FoxA factors, expressed in the foregut endoderm of the mouse,are necessary for
  • induction of the liver program.
    •  nearly one-third of the DNA sites bound by FoxA in the adult liver occur near silent genes.
organ regeneration example from induced plurip...

organ regeneration example from induced pluripotent stem cells(iPS cell) (Photo credit: Wikipedia)

English: Pathway of stem cell differentiation

English: Pathway of stem cell differentiation (Photo credit: Wikipedia)

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