Stress mediated changes in expression of the pkaC gene, encoding the catalytic subunit of cAMP-dependent protein kinase, in Aspergillus niger

The transcriptional regulation of the pkaC gene, encoding the catalytic subunit of cAMP-dependent protein kinase from Aspergillus niger was analysed under different environmental conditions. Quantitative determination of pkaC transcript showed a significant decrease in concentration of specific mRNA immediately after a temperature, hypoosmotic and hyperosmotic shock followed by stimulated synthesis. The amount of pkaC mRNA as well as PKA enzymatic activity steadily decreased during the initial phase of growth in 15 % sucrose medium while a slight increase was observed at the time of a change in morphology from bulbous cells to filamentous growth. Transcriptional alternation might be mediated by multiple putative stress elements in the promoter region of pkaC gene.