REGULATION OF TRANSCRIPTION OF THE CEL1 GENE IN AGARICUS-BISPORUS

Northern analysis showed that accumulation of Agaricus bisporus cel1 m RNA was regulated by two independent mechanisms: (i) induction by cell ulose; and (ii) repression by glucose and other sugars. Isolated A. bi sporus nuclei were transcriptionally active. Nuclei isolated from cell ulose-grown mycelium synthesized six times more cel1 mRNA than nuclei from glucose-grown mycelium. The start point of transcription (tsp) wa s identified by primer extension and S1 nuclease analysis. Putative gl ucose-, and cAMP-responsive elements as well as regions with homology to promoter regions of other fungal cellulase genes were detected both upstream and downstream from the tsp of the cel1 gene.