Aspergillus nidulans conidiation inducing factors FlbB and FlbF are localised in association with the polar growth machinery

Oier Etxebeste1, Aitor Garzia1, Eduardo A. Espeso2, Unai Ugalde1

Author address: 

1University of The Basque Country, Donostia-San Sebastian, Gipuzkoa, Spain, 2Centro de Investigaciones Biológicas (CSIC), Madrid, Spain


Asexual reproduction (conidiation) in Aspergillus nidulans is a complex morphogenetic process that requires the activation of the transcriptional regulator BrlA as the fisrt and central element. This depends on the action of upstream acting elements, which define the early induction pathway. This work presents new aspects on two of these upstream acting elements, FlbB and FlbF, and demonstrates that their action is also required beyond the upstream activation period. Both factors are probably located very close to or within the Spitzenkörper and backedby the endocytic machinery. Metabolic energy and an organised F-actin are required to maintain this location. FlbB is apically maintained throughout the cell cycle in vegetative cells. As yet unidentified processes provoke migration of FlbB to the most apical nucleus, where it purportedly binds DNA, as a bZIP transcription factor. On exposure to the air, FlbB is accumulated in all nuclei of the exposed hyphae, and during conidiophore development, it is located in elongating apex of the growing metulae. We conclude that FlbB and FlbF are associated to polar extension growth machinery where they apparently exert no majour role. They appear rather to fulfill a reporter function on suitable conditions for the onset of conidiogenesi

abstract No: 


Full conference title: 

    • ECFG 9th (2008)