Cell wall synthesis regulation in Saccharomyces cerevisiae. Effect of RNA and protein inhibition.

In this investigation the regulation of wall formation in Saccharomyces cerevisiae ts-136 (Hutchison, H.T., Hartwell, L.H. and McLaughlin, C.S. (1969) J. Bacteriol. 99, 807-814) was analyzed by following the inhibition of RNA and protein synthesis. Lomofungin, thiolutin and 8-hydroxyquinoline at the concentrations needed to inhibit RNA synthesis also produced inhibition of glucan and mannan synthetases. The synthesis of RNA was also blocked in S. cerevisiae ts-136 by incubation at the non-permissive temperature (37 degrees C). Mannan formation decreased steadily but glucan synthesis remained after 4 to 5 h. After a few minutes of blocking protein synthesis with cycloheximide mannan synthesis was also blocked whereas glucan formation was unaffected by the presence of the drug. These results suggest a high degree of stability for glucan synthetases. S. cerevisiae ts-136 after 2 h of incubation at the non-permissive temperature (37 degrees C) showed a preferential formation of wall materials (mannan and glucan) indicating that the RNA messengers which codify wall mannan peptides have a slower decay rate than those of the cytoplasmic proteins. The data presented indicate that the existence of stable glucan synthetases and RNA messengers of the wall mannan peptides of slow decay rate results in the continuous synthesis of glucans and mannoproteins of the yeast wall throughout the cell cycle.