Regulation of folate-dependent enzyme levels in Aspergillus nidulans: studies with regulatory mutants

摘要

The synthesis of folale-dependent enzymes in Asperailhis nidulans appears to be regulated by intracelliihir pools of homoeysteine and melliioniiie. The results are consistent with die view thai homoeysteine nets as an indueer and nielhionine as a corepressor, but the molecular ineehanisin of this regulation is still unknown. Methionine-reqiiiring mutants, metlll and nwlDIO, apparently allelic, show deregulation of lolate folate-dependent enzymes. Most characteristic of the mulants is a repressed level of I'olylpolygluianiate synthetase. New nuitutions suppressing the nu'tlll lesion which render folale enzymes insensitive to methionine-mediated repression have been isolated. These initiations me likely to identify new regulatory genes in folale metabolism.