digitonin in nuclei isolation buffer - why?

Don Newmeyer donald at ljcrf.edu
Wed Jan 12 19:33:49 EST 1994

 Melissa Melan   wrote:

>      The digitonin is most likely included in the isolation buffers as a
>disrupting agent that affects plasma membranes and not nuclear, mitochondrial orchloroplast 
>membranes.  Digitonin acts by dissrupting the association of
>cholesterol and phospholipids making "holes" in the membranes.  Nuclear
>envelope membranes have a much lower cholesterol content than plasma membranes
>and thus are less affected by digitonin or other  saponins.  I wouldn't bet
>my life though that its completely harmless to the nuclei.
>Hope that this helps.

That's right.  I might add that digitonin is routinely being used now to permeabilize cells for assaying 
import of nuclear proteins (Adam, S. A., Marr, R. S., and Gerace, L. (1990). Nuclear protein import in 
permeabilized mammalian cells requires soluble cytoplasmic factors. J. Cell Biol. 111: 807-816.) The 
method relies on the fact that digitonin at appropriate concentrations does not solubilize the nuclear 

Don Newmeyer
La Jolla Cancer Research Foundation
10901 N. Torrey Pines Rd.
La Jolla, CA  92037

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