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SUMMARY:Oct4-­Sox2protein dynamics characteristic of the pluripotent cell
  state
DTSTART:20120913T130000
DTSTAMP:20260427T200114Z
UID:735fcad985388ad594cf5ed102a56ae637322e30ac9c68b34e39fdd1
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Sohail Ahmed\, Institute of Medical Biology\, Singapore\nT
 he F--‐techniques\, FRET\, FLIM\, FCS\, FCCS are powerful approaches to 
 understand the mechanisms underlying cellular and developmental processess
 . Here we apply these imaging techniques to investigate pluripotency. Oct4
  and Sox2 are two essential transcription factors that co--‐regulate tar
 get genes for the maintenance of pluripotency. However\, it is unclear whe
 ther they interact prior to DNA binding or how the target sites are access
 ed in the nucleus. By generating fluorescent protein fusions of Oct4 and S
 ox2 that are functionally capable of producing induced pluripotent stem ce
 lls (iPSCs)\, we show that their interaction is dependent on the presence 
 of cognate DNA binding elements\, based on diffusion time\, complex format
 ion and lifetime measurements. Through fluorescence correlation spectrosco
 py\, the levels of Oct4 and Sox2 in the iPSCs were quantified in live cell
 s and two diffusion coefficients\, corresponding to free and loosely bound
  forms of the protein were distinguished. Notably\, the fraction of slow d
 iffusing molecules in the iPSCs was found to be elevated\, similar to the 
 profile in embryonic stem cells\, owed presumably to a change in the nucle
 ar milieu during reprogramming. Taken together\, these findings defined qu
 antitatively the amount of proteins pertinent to the pluripotent state and
  revealed increased accessibility to the underlying DNA as a mechanism for
  Oct4 and Sox2 to find their target binding sites and interact\, without p
 rior formation of heterodimer complexes.
LOCATION:AI 1153 https://plan.epfl.ch/?room==AI%201153
STATUS:CONFIRMED
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