Departamento de Genética, Universidad de Sevilla, Reina Mercedes s/n, 41012, Seville, Spain.
BMC Biol. 2022 Jun 27;20(1):149. doi: 10.1186/s12915-022-01351-x.
Fungi use light as an environmental signal to regulate developmental transitions that are key aspects of their biological cycles and that are also relevant for their dispersal and infectivity as plant or animal pathogens. In addition, light regulates the accumulation of photoprotective pigments, like carotenoids, and other secondary metabolites. Most fungal light responses occur after changes in gene transcription and we describe here a novel effect of light in the regulation of degradation of VE-1, a key component of the velvet complex, in the model fungus Neurospora crassa. The velvet complex is a fungal-specific protein complex that coordinates fungal development, secondary metabolism, and light regulation by interacting with other regulators and photoreceptors and modifying gene expression.
We have characterized the role of VE-1 during conidiation in N. crassa. In vegetative mycelia, VE-1 is localized in the cytoplasm and nuclei and is required for light-dependent transcription but does not interact with the photoreceptor and transcription factor WC-1. VE-1 is more stable in light than in darkness during asexual development (conidiation). We have shown that this light effect requires the blue-light photoreceptor WC-1. We have characterized the role of the proteasome, the COP9 signalosome (CSN), and the adaptor component of cullin-RING ubiquitin ligases, FWD-1, in the degradation of VE-1.
We propose that this new effect of light allows the fungal cell to adapt quickly to changes in light exposure by promoting the accumulation of VE-1 for the regulation of genes that participate in the biosynthesis of photoprotective pigments.
真菌将光作为环境信号来调节发育转变，这些转变是其生物周期的关键方面，也是其作为植物或动物病原体传播和感染性的关键方面。此外，光还调节光保护色素（如类胡萝卜素）和其他次生代谢物的积累。大多数真菌的光反应发生在基因转录变化之后，我们在这里描述了光在调节模型真菌粗糙脉孢菌（Neurospora crassa）中 VE-1 降解中的一种新作用。 velvet 复合物是一种真菌特异性蛋白复合物，通过与其他调节剂和光受体相互作用并修饰基因表达，协调真菌发育、次生代谢和光调节。
我们已经研究了 VE-1 在粗糙脉孢菌的分生孢子形成过程中的作用。在营养菌丝体中，VE-1 定位于细胞质和细胞核中，是光依赖性转录所必需的，但不与光受体和转录因子 WC-1 相互作用。在无性发育（分生孢子形成）过程中，VE-1 在光下比在黑暗中更稳定。我们已经证明，这种光效应需要蓝光受体 WC-1。我们已经研究了蛋白酶体、COP9 信号小体（CSN）和 cullin-RING 泛素连接酶的衔接子成分 FWD-1 在 VE-1 降解中的作用。
我们提出，这种光的新作用允许真菌细胞通过促进 VE-1 的积累来快速适应光暴露的变化，从而调节参与光保护色素生物合成的基因。
