Preformed messengers in Microsporum canis macroconidia.

ABSTRACT

Macroconidia of Microsporum canis, when placed in a nutrient medium produce germ tubes within 4–6 h. Precursor incorporation studies showed that protein synthesis occurred prior to RNA synthesis. Sucrose density gradient analysis of wet and dry spore extracts revealed the presence of 16 % and 11 % polysomes respectively. The polysomal content increased to about 50% within 15 min of germination. Synthesis of RNA occurred only after 2 h of germination. Pool equilibration of the radioactive precursors was not limiting to these measurements. Polyadenylated RNA was isolated from macroconidia and was found to comprise 2-2·5 % of the total RNA. The poly(A)+ RNAs were heterodisperse and translatable in a wheat germ cell free translating system. It was concluded that macroconidia of Microsporum canis contain pre-formed mRNA which is translated early in germination.