Marzluf G A
Department of Biochemistry and Program in Molecular, Cellular, and Developmental Biology, The Ohio State University, Columbus 43210, USA.
Annu Rev Microbiol. 1997;51:73-96. doi: 10.1146/annurev.micro.51.1.73.
The filamentous fungi Aspergillus nidulans and Neurospora crassa and the yeast Saccharomyces cerevisiae each possess a global regulatory circuit that controls the expression of permeases and enzymes that function both in the acquisition of sulfur from the environment and in its assimilation. Control of the structural genes that specify an array of enzymes that catalyze reactions of sulfur metabolism occurs at the transcriptional level and involves both positive-acting and negative-acting regulatory factors. Positive trans-acting regulatory proteins that contain a basic region, leucine zipper-DNA binding domain, are found in Neurospora and yeast. Each of these fungi contain a sulfur regulatory protein of the beta-transducin family that acts in a negative fashion to control gene expression. Sulfur regulation in yeast also involves the general DNA binding protein, centromere binding factor I. Sulfate uptake is a highly regulated step and appears to occur in fungi, plants, and mammals via a family of related transporter proteins. Recent developments have provided new insight into the nature and control of the enzymes ATP sulfurylase and APS kinase, which catalyze the early steps of sulfate assimilation, and of the Aspergillus enzyme, cysteine synthase, which produces cysteine from O-acetylserine.
丝状真菌构巢曲霉和粗糙脉孢菌以及酿酒酵母都拥有一个全局调控回路，该回路控制着通透酶和酶的表达，这些通透酶和酶在从环境中获取硫及其同化过程中发挥作用。指定一系列催化硫代谢反应的酶的结构基因的调控发生在转录水平，涉及正调控因子和负调控因子。在粗糙脉孢菌和酵母中发现了含有碱性区域、亮氨酸拉链 - DNA 结合结构域的正向反式作用调控蛋白。这些真菌中的每一种都含有β - 转导蛋白家族的硫调控蛋白，该蛋白以负向方式控制基因表达。酵母中的硫调控还涉及一般的 DNA 结合蛋白，着丝粒结合因子 I。硫酸盐摄取是一个受到高度调控的步骤，在真菌、植物和哺乳动物中似乎是通过一族相关的转运蛋白发生的。最近的研究进展为催化硫酸盐同化早期步骤的酶 ATP 硫酸化酶和 APS 激酶以及从 O - 乙酰丝氨酸产生半胱氨酸的曲霉酶半胱氨酸合酶的性质和调控提供了新的见解。
