ATP-Citrate Lyase Is Required for Production of Cytosolic Acetyl Coenzyme A and Development in Aspergillus nidulans
ATP-Citrate Lyase Is Required for Production of Cytosolic Acetyl Coenzyme A and Development in Aspergillus nidulans
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DOI：
10.1128/ec.00080-10
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发表时间：
2010-07-01
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影响因子：
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通讯作者：
Murray, Sandra L.
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文献类型：
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作者：
Hynes, Michael J.;Murray, Sandra L.
乙酰辅酶A（CoA）是碳和能量代谢以及细胞分子生物合成中的中心代谢物。细胞质乙酰辅酶A的来源对于脂肪酸和固醇的产生以及蛋白质乙酰化（包括细胞核中的组蛋白乙酰化）是必需的。在酿酒酵母和白色念珠菌中，乙酰辅酶A通过细胞质乙酰辅酶A合成酶从乙酸产生，而在植物和动物中，乙酰辅酶A通过ATP-柠檬酸裂解酶从柠檬酸衍生。在丝状子囊菌构巢曲霉，串联分歧转录基因（aclA和aclB）编码的ATP-柠檬酸裂解酶的亚基，我们已经删除了这些基因。生长在不产生细胞质乙酰辅酶A的碳源（如葡萄糖和脯氨酸）上大大减少，而生长在产生细胞质乙酰辅酶A的碳源（如乙酸盐和乙醇）上不受影响。添加乙酸盐可恢复葡萄糖或脯氨酸的生长，这依赖于编码细胞质乙酰辅酶A合成酶的facA，而不依赖于调节基因facB。aclA和aclB的转录受到乙酸盐或乙醇生长的抑制。ATP-柠檬酸裂解酶的丧失导致严重的发育影响，无性孢子（分生孢子）的产生大大减少，完全没有性发育。这与大孢囊壳菌相反，在大孢囊壳菌中，子实体的形成被启动，但在ATP-柠檬酸裂解酶突变体中成熟是有缺陷的。添加乙酸不能修复这些缺陷，表明在分化过程中对高水平的细胞质乙酰辅酶A的特定要求。所有表型的aclA和aclB缺失之间的异核体互补表明串联基因排列不是必需的。
Acetyl coenzyme A (CoA) is a central metabolite in carbon and energy metabolism and in the biosynthesis of cellular molecules. A source of cytoplasmic acetyl-CoA is essential for the production of fatty acids and sterols and for protein acetylation, including histone acetylation in the nucleus. In Saccharomyces cerevisiae and Candida albicans acetyl-CoA is produced from acetate by cytoplasmic acetyl-CoA synthetase, while in plants and animals acetyl-CoA is derived from citrate via ATP-citrate lyase. In the filamentous ascomycete Aspergillus nidulans, tandem divergently transcribed genes (aclA and aclB) encode the subunits of ATP-citrate lyase, and we have deleted these genes. Growth is greatly diminished on carbon sources that do not result in cytoplasmic acetyl-CoA, such as glucose and proline, while growth is not affected on carbon sources that result in the production of cytoplasmic acetyl-CoA, such as acetate and ethanol. Addition of acetate restores growth on glucose or proline, and this is dependent on facA, which encodes cytoplasmic acetyl-CoA synthetase, but not on the regulatory gene facB. Transcription of aclA and aclB is repressed by growth on acetate or ethanol. Loss of ATP-citrate lyase results in severe developmental effects, with the production of asexual spores (conidia) being greatly reduced and a complete absence of sexual development. This is in contrast to Sordaria macrospora, in which fruiting body formation is initiated but maturation is defective in an ATP-citrate lyase mutant. Addition of acetate does not repair these defects, indicating a specific requirement for high levels of cytoplasmic acetyl-CoA during differentiation. Complementation in heterokaryons between aclA and aclB deletions for all phenotypes indicates that the tandem gene arrangement is not essential.