ADP-ribosylation of myelin basic proteins isolated from normal and mutant mouse brains.

Myelin basic proteins (MBPs) have been shown to be ADP-ribosylated in-vitro by cholera toxin in the presence of NAD. Since acid-soluble extracts of brain contain other proteins in the 14-32 kD range (such as histones) in addition to MBP's, the identification of the ADP-ribosylated proteins was uncertain. To determine that only the MBP's were ADP-ribosylated, the acid-soluble fractions from several murine mutants were prepared. Thus, in the Shiverer mutants, none of the proteins in the 14-32 kD range were ADP-ribosylated; in the Myelin-deficient mutant, some of ADP-ribosylation was observed but none in the Jimpy mutant, consistent with our demonstration that the least cationic isomer cannot be ADP-ribosylated.