Identification of a putative FR901469 biosynthesis gene cluster in fungal sp. No. 11243 and enhancement of the productivity by overexpressing the transcription factor gene frbF

Gα signaling pathway as well as the global regulator LaeA were demonstrated to positively regulate the biosynthesis of chaetoglobosin A (ChA), a promising biotic pesticide produced by Chaetomium globosum. Recently, the regulatory function of Zn2Cys6 binuclear finger transcription factor CgcheR that lies within the ChA biosynthesis gene cluster has been confirmed. However, CgcheR was not merely a pathway specific regulator. In this study, we showed that the homologs gene of CgcheR (designated as Cgtf1) regulate ChA biosynthesis and sporulation in C. globosum NK102. More importantly, RNA-seq profiling demonstrated that 1,388 genes were significant differentially expressed as Cgtf1 deleted. Among them, a putative C2H2 transcription factor, named Cgtf6, showed the highest gene expression variation in zinc-binding proteins encoding genes as Cgtf1 deleted. qRT-PCR analysis confirmed that expression of Cgtf6 was significantly reduced in CgTF1 null mutants. Whereas, deletion of Cgtf6 resulted in the transcriptional activation and consequent increase in the expression of ChA biosynthesis gene cluster and ChA production in C. globosum. These data suggested that CgTF6 probably acted as an end product feedback effector, and interacted with CgTF1 to maintain a tolerable concentration of ChA for cell survival.

Download Full-text

AraC-like transcriptional activator CuxR binds c-di-GMP by a PilZ-like mechanism to regulate extracellular polysaccharide production

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1702435114 ◽

2017 ◽

Vol 114 (24) ◽

pp. E4822-E4831 ◽

Cited By ~ 24

Author(s):

Simon Schäper ◽

Wieland Steinchen ◽

Elizaveta Krol ◽

Florian Altegoer ◽

Dorota Skotnicka ◽

...

Keyword(s):

Transcription Factor ◽

Molecular Evolution ◽

Dna Binding ◽

Gene Cluster ◽

Sinorhizobium Meliloti ◽

Extracellular Polysaccharide ◽

Extracellular Polysaccharides ◽

Biosynthesis Gene Cluster ◽

Biosynthesis Gene ◽

Helical Hairpin

Cyclic dimeric GMP (c-di-GMP) has emerged as a key regulatory player in the transition between planktonic and sedentary biofilm-associated bacterial lifestyles. It controls a multitude of processes including production of extracellular polysaccharides (EPSs). The PilZ domain, consisting of an N-terminal “RxxxR” motif and a β-barrel domain, represents a prototype c-di-GMP receptor. We identified a class of c-di-GMP–responsive proteins, represented by the AraC-like transcription factor CuxR in plant symbiotic α-proteobacteria. In Sinorhizobium meliloti, CuxR stimulates transcription of an EPS biosynthesis gene cluster at elevated c-di-GMP levels. CuxR consists of a Cupin domain, a helical hairpin, and bipartite helix-turn-helix motif. Although unrelated in sequence, the mode of c-di-GMP binding to CuxR is highly reminiscent to that of PilZ domains. c-di-GMP interacts with a conserved N-terminal RxxxR motif and the Cupin domain, thereby promoting CuxR dimerization and DNA binding. We unravel structure and mechanism of a previously unrecognized c-di-GMP–responsive transcription factor and provide insights into the molecular evolution of c-di-GMP binding to proteins.

Download Full-text

Frequency of three mutations in the fumonisin biosynthetic gene cluster of Fusarium fujikuroi that are predicted to block fumonisin production

World Mycotoxin Journal ◽

10.3920/wmj2020.2572 ◽

2021 ◽

Vol 14 (1) ◽

pp. 49-59

Author(s):

S. Sultana ◽

W.X. Bao ◽

M. Shimizu ◽

K. Kageyama ◽

H. Suga

Keyword(s):

Transcription Factor ◽

Secondary Metabolites ◽

Gene Cluster ◽

Biosynthetic Gene Cluster ◽

Pcr Analysis ◽

Fusarium Fujikuroi ◽

Biosynthetic Gene ◽

Transcription Factor Gene ◽

Factor Gene ◽

Group Strain

Fusarium fujikuroi is the most prominent pathogen found in rice. In addition to gibberellin, F. fujikuroi produces various secondary metabolites, including the polyketide mycotoxins, fumonisins. Fumonisin production is conferred by the fumonisin biosynthetic gene (FUM) cluster consisting of 15-17 genes. F. fujikuroi is phylogenetically subclassified into one group with fumonisin production (F-group) and another group in which fumonisin production is undetectable (G-group). In a previous study, a G-to-T substitution (FUM21_G2551T) in the FUM cluster transcription factor gene, FUM21, was identified as a cause of fumonisin-non-production in a G-group strain. In the current study, further analysis of G-group strains identified two additional mutations that involved FUM-cluster genes essential for fumonisin production: (1) a 22.4-kbp deletion in the FUM10-FUM19 region; and (2) a 1.4-kbp insertion in FUM6. PCR analysis of 44 G-group strains, indicated that 84% had the FUM21_G2551T mutation, 50% had the 22.4-kbp FUM10-FUM19 deletion, and 32% had the 1.4-kbp insertion in FUM6, and some strains had two or all the mutations. None of the mutations were detected in the 51 F-group strains examined. Each of the three mutations alone could account for the lack of fumonisin production in G-group strains. However, one G-group strain did not have any of the mutations. Therefore, another mutation(s) is likely responsible for the lack of fumonisin production in some G-group strains of F. fujikuroi.

Download Full-text