Plastic Rewiring of Sef1 Transcriptional Networks and the Potential of Nonfunctional Transcription Factor Binding in Facilitating Adaptive Evolution.
Mol Biol Evol, 2021/10/27;38(11):4732-4747.
Hsu PC[1], Lu TC[2, 3], Hung PH[1, 4], Jhou YT[1], Amine AAA[1, 5], Liao CW[1], Leu JY[1, 4, 5]
Affiliations
PMID: 34175931DOI: 10.1093/molbev/msab192
Impact factor: 8.8
Abstract
Prior and extensive plastic rewiring of a transcriptional network, followed by a functional switch of the conserved transcriptional regulator, can shape the evolution of a new network with diverged functions. The presence of three distinct iron regulatory systems in fungi that use orthologous transcriptional regulators suggests that these systems evolved in that manner. Orthologs of the transcriptional activator Sef1 are believed to be central to how iron regulatory systems developed in fungi, involving gene gain, plastic network rewiring, and switches in regulatory function. We show that, in the protoploid yeast Lachancea kluyveri, plastic rewiring of the L. kluyveri Sef1 (Lk-Sef1) network, together with a functional switch, enabled Lk-Sef1 to regulate TCA cycle genes, unlike Candida albicans Sef1 that mainly regulates iron-uptake genes. Moreover, we observed pervasive nonfunctional binding of Sef1 to its target genes. Enhancing Lk-Sef1 activity resuscitated the corresponding transcriptional network, providing immediate adaptive benefits in changing environments. Our study not only sheds light on the evolution of Sef1-centered transcriptional networks but also shows the adaptive potential of nonfunctional transcription factor binding for evolving phenotypic novelty and diversity.
Keywords: Lachancea kluyveri ; TCA cycle regulation; nonfunctional transcription factor binding; phenotypic diversity; transcriptional network evolution; transcriptional rewiring
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