Oiartzabal-Arano Elixabet, Garzia Aitor, Gorostidi Ana, Ugalde Unai, Espeso Eduardo A, Etxebeste Oier
Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, Manuel de Lardizabal, 3, 20018, San Sebastian, Spain.
Biodonostia Research Institute, Genomic Platform, Doctor Begiristain, s/n, 20014, San Sebastian, Spain.
Genetics. 2015 Apr;199(4):1127-42. doi: 10.1534/genetics.115.174342. Epub 2015 Feb 20.
In the model fungus Aspergillus nidulans, asexual development is induced from vegetative hyphae by a set of early regulators including the bZIP-type transcription factor FlbB. To determine the range of genes under the influence of the transcriptional activity of FlbB and to characterize their role in fungal development, we sequenced and compared the transcriptomes of a ΔflbB mutant and its isogenic wild-type strain at different developmental stages. Results confirmed the activating role of FlbB on downstream regulators of conidiation such as flbD and brlA. However, FlbB has additional functions beyond the induction of asexual development. Among the changes observed, absence of a functional FlbB caused induction of the dba cluster and synthesis of a secondary metabolite with bactericidal properties. In addition, a new transcriptional target of FlbB was unveiled, urdA, that codes for a putative transcription factor that represses premature sexual development. Taken together, our results indicate that the activators of asexual development simultaneously exert a role on other cellular functions, including an inhibitory effect on the sexual cycle, and reinforce the hypothesis that mutually exclusive metabolic and cellular patterns are associated with different morphogenetic programs.
在模式真菌构巢曲霉中，包括bZIP型转录因子FlbB在内的一组早期调控因子可诱导无性发育从营养菌丝开始。为了确定受FlbB转录活性影响的基因范围，并表征它们在真菌发育中的作用，我们对ΔflbB突变体及其同基因野生型菌株在不同发育阶段的转录组进行了测序和比较。结果证实了FlbB对分生孢子形成的下游调控因子如flbD和brlA的激活作用。然而，FlbB除了诱导无性发育外还有其他功能。在所观察到的变化中，功能性FlbB的缺失导致dba簇的诱导以及具有杀菌特性的次生代谢产物的合成。此外，还揭示了FlbB的一个新的转录靶点urdA，它编码一种假定的转录因子，可抑制过早的有性发育。综上所述，我们的结果表明无性发育的激活因子同时对其他细胞功能发挥作用，包括对有性周期的抑制作用，并强化了相互排斥的代谢和细胞模式与不同形态发生程序相关的假说。
