The Effect of Light on the Composition of DNA‐dependent RNA Polymerases of Verticillium agaricinum

Abstract

AbstractFour cellular RNA polymerases have been partially purified from cultures of Verticillium agaricinum using DEAE‐cellulose chromatography. Polymerases 1 and II are probably localised in the nucleolus and non‐nucleolar portion of the nucleus respectively, while III and IV are probably mitochondrial in origin. DNA stimulation and dependency on the four ribonucleoside triphosphates were shown to be characteristic of all four polymerases. The products of their activity were sensitive to ribonuclease digestion and to KOH hydrolysis. The time course study of all four polymerases showed a linear increase for 1 min followed by a plateau and a rapid decrease after 5 min.Illumination of 4‐day‐old cultures increases the activity of RNA polymerase I, II, and III while only that of I and III is increased in 7‐day cultures. There is a similar increase in the amount of carotenoids produced by 4‐ and 7‐day‐old illuminated cultures. It is tempting therefore to suggest that ribosomes or mitochondria or both may be implicated in light‐induced cartogenesis.