DNA Laddering and Apoptosis

Tom Maynard maynard at oregon.uoregon.edu
Wed Nov 19 23:01:14 EST 1997

CAMANDAT at BIOLOGY.watstar.uwaterloo.ca (Craig A. Mandato) writes:

>I have a quick question regarding the DNA fragmentation which takes place 
>during the intermediate phase of apoptosis. What "exactly" causes the 
>discrete banding pattern and why are there even increments of DNA bands; 
>ie., why don't you get a smear.

Various cell signalling cascades activate DNA degrading enzymes (endonucleases)
which cut up the genomic DNA.  These tend to cut in the spaces between
histones, leaving bands at approximately 200bp multiples.

I'm not sure if I'd refer to DNA fragmentation as an "intermediate" phase,
however -- I'm pretty sure it's quite terminal.

--Tom Maynard
  Lab Slave

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