NAD+ loading of mammalian cells by electrotransfection leads to increased poly(ADP-ribosyl)ation capacity.
Many cellular enzymes use NAD+ as coenzyme or substrate, depending on the nature of the enzymatic reaction. Under certain conditions the cellular NAD+ concentration may become rate-limiting for such enzymes. For instance, when eucaryotic cells are exposed to high concentrations of DNA-damaging agents, the resulting DNA strand breaks may stimulate the nuclear enzyme poly(ADP-ribose) polymerase (PARP) to such an extent that the cellular pool of NAD+, which is the substrate for this enzyme, is severely depleted, possibly leading to acute cell death. Here we show that NAD+ concentrations in CV-1 monkey and CO60 hamster cells can be raised 3- to 4-fold by electrotransfection of NAD+. This additional NAD+ is indeed available for PARP to synthesize higher-than-normal amounts of poly(ADP-ribose) after treatment with the alkylating agent N-methyl-N'-nitro-N-nitrosoguanidine. NAD+ loading of cells by electrotransfection may be useful also for the study of other cellular reactions in which NAD+ is involved.
Küpper
J H
JH
Deutsches Krebsforschungszentrum, Abteilung 0610, Heidelberg, Germany.
Wolf
I
I
Bürkle
A
A
D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D018736:DNA Adducts; D018274:Electroporation; D005455:Fluorescent Antibody Technique; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D009243:NAD / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000096:biosynthesis*
D018736:DNA Adducts; D009243:NAD; D008769:Methylnitronitrosoguanidine; D011065:Poly(ADP-ribose) Polymerases