The terrein biosynthetic gene cluster of Aspergillus terreus: structure, function, regulation, and similar gene clusters

Fungi synthesize a wide variety of secondary metabolites (SMs). The genes of the biosynthetic pathways of many of these compounds are encoded by biosynthetic gene clusters (BGCs), which typically consist of a core biosynthetic enzyme, tailoring enzymes, transporters, and pathway-specific regulators. One of the well-studied fungal SMs is the polyketide terrein, which is produced by Aspergillus terreus and exhibits a wide range of biological activities, such as cytotoxic, phytotoxic, and antibacterial effects. The structure and function of the terrein BGC, the functions of the encoded proteins, and the processes controlling the transcriptional regulation of the BGC are summarized in this mini review. Both pathway-specific and global regulators and epigenetic regulation are presented. Furthermore, similar BGCs identified in other fungal taxa are introduced in short. Despite significant advances, key aspects of terrein biosynthesis, such as some protein functions, details of the BGC regulation, and SM ecological functions remain unresolved. Filling in these gaps will help us better understand the biology of fungal SMs and could pave the way for biotechnological applications.