Abstract
Summary: The interaction between genes of Aspergillus nidulans conferring constitutive synthesis of isocitrate lyase (iclcA and iclcB) and fluoroacetate resistance (facB) has been investigated. Although facB mutants are unable to induce the glyoxylate cycle enzyme isocitrate lyase in response to acetate as sole carbon source, this phenotype was suppressed in recombinants of the type iclc;facB. The iclcA and iclcB mutations do not alter significantly the activities of eight enzymes of intermediary metabolism assayed. We conclude that the iclc genes are probably bona fide isocitrate lyase regulatory genes.