2012 Fanglan Dai Academic Forum (1): Cellular Morphogenesis During Development in the Fungus Aspergillus nidulans.

Title: Cellular Morphogenesis During Development in the Fungus Aspergillus nidulans.

Presenter: Steven Harris

Time: May7, 2012 Monday, 10:00-11:30am

Vennue: IMCAS A203#

Chair: Prof. Shaojie Li

Abstract:

Because of its genetic tractability and amenability to post-genome analysis, A. nidulans is one of the best-established model filamentous fungi. A primary focus of research using A. nidulans has been to understand the mechanisms that direct cellular morphogenesis during hyphal growth and reproductive development. Although A. nidulans is capable of generating a variety of cell shapes, these variations likely reflect differences in the timing and location of polarized growth. Thus, elucidating the regulatory networks that determine where and when the morphogenetic machinery (i.e., the components of the cytoskeleton and vesicle trafficking complexes that enable polarized growth) is deployed should provide fundamental insight into cellular morphogenesis. Towards this end, we have focused our efforts on A. nidulans homologues of the yeast bud site selection proteins and the Cdc42/Rac1 GTPase module. Our results implicate these homologues in specific aspects of hyphal morphogenesis, including septum formation and branching. Moreover, these homologues also perform critical functions during conidiophore development. In particular, the Cdc42/Rac1 module regulates formation of the terminal vesicle and is also required for the formation of normal metulae and phialides. In addition, the homologue of the bud site marker protein Axl2 controls phialide morphogenesis and likely coordinates the transition from acropetal to basipetal growth that underlies spore formation. Collectively, our results provide new insight into the regulatory mechanisms that differentially regulate cellular morphogenesis during growth and development in A. nidulans.