Reversal of Multicellular-form Development in a Conditional Morphological Mutant of the Fungus Wangiella dermatitidis

Abstract

Summary: Yeast cells of the temperature-sensitive morphological mutant strain Mc3 of the polymorphic fungus Wangiella dermatitidis were allowed to initiate multicellular-form development at the restrictive temperature (37 °C), then induced to resume budding yeast growth by downshift to the permissive temperature (25 °C). The kinetics of the resumption of yeast budding were investigated, and the dependence of bud initiation upon DNA synthesis, protein synthesis and microtubule function was probed. The results indicated that the thermolabile event in strain Mc3 was a cell cycle event involved in yeast budding, and that developing multicellular forms retained most of the machinery necessary to reinitiate budding. However, initiation of budding required the synthesis of protein, and possibly RNA, suggesting that one or more proteins involved in initiation of budding were not present in the developing multicellular forms.