CELL-WATER DEFICIT REGULATES EXPRESSION OF RPOC1C2 (RNA-POLYMERASE) AT THE LEVEL OF MESSENGER-RNA IN DESICCATION-TOLERANT NOSTOC COMMUNE UTEX-584 (CYANOBACTERIA)

Immobilization and short-term air-drying of the cyanobacterium Nostoc commune strain UTEX 584 leads to a complete depletion of its cellular rpoC1C2 mRNA pool. This mRNA is required for the synthesis of the gamm a and beta' subunits of DNA-dependent RNA polymerase (RNA-P). In contr ast, RNA-P remains stable in cells during long-term desiccation as jud ged from immunoblotting analyses of protein extracts using RNA-P core- specific antibodies. The data indicate that the extant RNA-P holoenzym e in air-dried cells drives the rapid de novo transcription of rpoC1C2 that ensues in response to cell rehydration.