title: Basic-zipper-type transcription factor FlbB controls asexual development in Aspergillus nidulans.
abstract: The fungal colony is a complex multicellular unit consisting of various cell types and functions. Asexual spore formation (conidiation) is integrated through sensory and regulatory elements into the general morphogenetic plan, in which the activation of the transcription factor BrlA is the first determining step. A number of early regulatory elements acting upstream of BrlA (fluG and flbA-E) have been identified, but their functional relations remain to be further investigated. In this report we describe FlbB as a putative basic-zipper-type transcription factor restricted to filamentous fungi. FlbB accumulates at the hyphal apex during early vegetative growth but is later found in apical nuclei, suggesting that an activating modification triggers nuclear import. Moreover, proper temporal and quantitative expression of FlbB is a prerequisite for brlA transcription, and misscheduled overexpression inhibits conidiation. We also present evidence that FlbB activation results in the production of a second diffusible signal, acting downstream from the FluG factor, to induce conidiation.
authors.affiliation: University of The Basque Country, Biochemistry II, Manuel de Lardizabal 3, 20018, San Sebastian, Spain.
authors.forename: Oier
authors.initials: O
authors.lastname: Etxebeste
authors.forename: Min
authors.initials: M
authors.lastname: Ni
authors.forename: Aitor
authors.initials: A
authors.lastname: Garzia
authors.forename: Nak-Jung
authors.initials: NJ
authors.lastname: Kwon
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fischer
authors.forename: Jae-Hyuk
authors.initials: JH
authors.lastname: Yu
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Espeso
authors.forename: Unai
authors.initials: U
authors.lastname: Ugalde
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D025301:Hyphae; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D012331:RNA, Fungal / Q000235:genetics / Q000378:metabolism; D012100:Reproduction, Asexual / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D013172:Spores, Fungal / Q000502:physiology; D015533:Transcriptional Activation
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D004271:DNA, Fungal; D005656:Fungal Proteins; D012331:RNA, Fungal