The bZIP8208;type transcription factor FlbB: A versatile regulator of Aspergillus nidulans asexual development.

Oier Etxebeste, Aitor Garzia, Erika Herrero-Garcí­a, Marc S. Cortese, Eduardo A. Espeso, Unai Ugalde

Author address: 

Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, Manuel de Lardizabal 3, 20018, San Sebastian, Spain.  Â  2. Dept. Medicina Molecular y Celular, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu,

Abstract: 

The early stages of asexual development in the model fungus Aspergillus nidulans are controlled at the molecular level by a discrete number of regulatory proteins that includes the bZIP8208;type transcription factor (TF) FlbB. Vegetative hyphae contain two main pools of FlbB, one at the tip and the other at the most apical nucleus. The apical pool requires the interaction with the positional regulator FlbE at or in the proximity of the Spitzenkörper. This interaction requires in FlbB a functional bZIP domain, specific central regions and a highly conserved Cys residue. Nuclear FlbB is renewed after each mitotic cycle and under appropriate conditions, activates the cMyb8208; type TF FlbD. Both factors, in turn, jointly activate the expression of the conidiation8208;specific TF brlA. A 2D8208;PAGE screening of proteins in wild type and 8710;flbB strains showed that the concentration of specific stress8208; response proteins was controlled through FlbB. gmcA, a previously uncharacterized glucose8208;methanol8208;choline oxidoreductase coding gene, shows miss8208;scheduled expression in a  916;flbB genetic background and the derived protein is required during development under alkaline pH conditions. Sequencing of mRNA from both vegetative and asexual samples provides for a wide overview on the genes and pathways under the hypothetic transcriptional control of FlbB activity. Preliminary results obtained in the functional characterization of some of these genes are also presented. Overall, the functional versatility of FlbB provides for a new outlook on morphogenetic change and focuses our future work on the study of the molecular mechanisms through which this TF regulates different cellular processes during development.
2012

abstract No: 

PR7.2

Full conference title: 

11 th European Conference on Fungal Genetics
    • ECFG 11th (2012)