A septin from the filamentous fungus A. nidulans induces atypical pseudohyphae in the budding yeast S. cerevisiae

Authors: Lindsey, Rebecca; HA, YOUNGSIL - University Of Georgia; MOMANY, MICHELLE - University Of Georgia

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2010
Publication Date: 5/25/2010
Citation: Lindsey, R.L., Ha, Y., Momany, M. 2010. A septin from the filamentous fungus A. nidulans induces atypical pseudohyphae in the budding yeast S. cerevisiae. PLoS One. 5(3):e9858. 1-9.

Interpretive Summary: The cell shape or morphology of many fungal species is very plastic, changing dramatically in response to changes in the cellular environment. This plasticity, or ability to change, is thought to enhance the survival of fungi in different environments. There is increasing evidence from a variety of systems that septins play critical roles in directing cell shape. In yeasts (like bakers yeast) septins form rings at the base of emerging round buds. In filamentous fungi septins form rings at the bases of emerging hyphae. The introduction of the filamentous fungus Aspergillus nidulans septin AspC into the yeast Saccharomyces cerevisiae induces a shift from formation of buds to formation of atypical pseudohyphae. This suggests that septins may play an important role in the ability of fungi to change shape which enhances their survival by allowing them to alter their growth modes to better cope with hostile environments.

Technical Abstract: Septins were first discovered in Saccharomyces cerevisiae where they form a scaffold that organizes the bud site and are a component of the morphogenesis checkpoint that coordinates budding with mitosis. Five of the seven S. cerevisiae septins (Cdc3, Cdc10, Cdc11, Cdc12 and Shs1) colocalize as a ring or collar to the neck region where the daughter bud emerges from the mother cell. At least 35 other proteins, including cell wall biosynthetic enzymes and cell cycle regulators, localize to the bud neck region in a septin-dependent manner. Mutation of any of the core septins, CDC3, CDC10, CDC11, or CDC12, prevents formation of the septin ring, resulting in elongated buds and mitotic delay. In the filamentous fungus Aspergillus nidulans four of the five septins (AspA, AspB, AspC and AspD) are orthologs of the S. cerevisiae core septins and localize as a ring or collar to the region where the hypha emerges from the conidium. AspC is orthologous to S. cerevisiae Cdc12. When introduced into the yeast Saccharomyces cerevisiae, the septin AspC from the filamentous fungus Aspergillus nidulans induced highly elongated atypical pseudohyphae. This suggests that septins may play an important role in the morphological plasticity of fungi to enhance their survival by allowing them to alter their growth modes to better cope with hostile environments.