Some aspects of the regulation of pyruvate kinase levels in Neurospora crassa

Abstract

Pyruvate kinase levels were monitored in Neurospora crassa mycelium (grown on different carbon sources for varying time intervals) by immunoprecipitation using polyclonal antibodies raised against a purified enzyme preparation. Pyruvate kinase specific mRNA was demonstrated by hybridization of Northern and dot blots of total RNA with a N. crassa pyruvate kinase gene fragment. Two pyruvate kinase specific mRNA species were detected in mycelia of all ages examined. An age-dependent and carbon source dependent variation in the pyruvate kinase protein and mRNA levels was encountered: (i) both registered an increase for up to about 20 h and a subsequent decline; (ii) growth on acetate and sucrose resulted in significantly higher yields of both, relative to that on medium containing ethanol and alanine. Stress caused by heat shock depressed the pyruvate kinase mRNA levels.