A study of the messenger RNA encoding pyruvate kinase of Neurospora crassa

In Neurospora crassa, there is a single pyruvate kinase (PK) consisting of four identical subunits of approximately 60k daltons. Northern and dot blot hybridization studies, using most of the yeast pyruvate kinase gene as a probe, suggest the presence of two distinct mRNA species for pyruvate kinase, separable on the basis of the length of their polyadenylated tails, by oligo(dT)cellulose chromatography. These messages are present in polysomes, immuno-precipitated by anti-PK antibodies, indicating probable translation in vivo. Fractions containing both messages were translated in vitro in the heterologous systems as well as in a homologous N. crassa lysate, the newly-synthesized PK being detected by immunoadsorption. Protection studies using S1-nuclease suggest no major structural differences in the 5'-untranslated and most of the coding regions of the two messages.