Examining the Evolution of the Regulatory Circuit Controlling Secondary Metabolism and Development in the Fungal Genus Aspergillus
Fig 5
Model of the evolution of the regulatory circuit controlling secondary metabolism and development in Aspergillus.
Generalized gene regulatory networks for development (A,B) and secondary metabolism (C,D) for the transcriptional regulators VeA (A,C) and MtfA (B,D) in A. fumigatus and A. nidulans. As master transcriptional regulators, VeA and MtfA can promote the expression of a gene (indicated by an arrow →) or suppress it (indicated by a bar ⟞). Target genes are either conserved (i.e., present in both species; green squares) or not (i.e., species-specific; blue squares). Similarly, the signal emanating from each transcriptional regulator that coordinates target gene regulation is either conserved (i.e., acting in the same fashion on genes conserved in both species; green arrows/bars) or not (i.e., acting in different fashion on genes conserved in both species or acting on species-specific genes; blue arrows/bars). Both transcriptional regulators contribute to the regulation of secondary metabolism in both A. fumigatus and A. nidulans even though the underlying genes in the two species are largely non-homologous (C,D). In contrast, the role of these two regulators in development, where most underlying genes are conserved in both species, is different; the role of veA is conserved, but mtfA regulates development in the homothallic A. nidulans but not in the heterothallic A. fumigatus (A,B).