Xanthine dehydrogenase (XDH) cross-reacting material in mutants of Drosophila melanogaster deficient in XDH activity

Rocket immunoelectrophoresis was used to estimate xanthine dehydrogenase cross-reacting material (XDH-CRM) in strains containing the cin ¹ and cin ⁹ mutant genes, which are deficient in XDH enzymatic activity. CRM levels were determined as percentages of CRM in the Oregon-R wild-type strain. The mutant strains contain 72 and 76% of Oregon-R CRM, respectively. CRM levels in strains containing the XDH-deficient mutant genes lxd and mal are 93 and 105%, respectively. The high levels of CRM in these four mutant strains indicate that the primary effects of the mutant genes are on the function of XDH protein rather than its accumulation.This research was supported by a grant from the Natural Sciences and Engineering Research Council of Canada to L. W. B.