POSITIVE REGULATION IN THE GENERAL AMINO-ACID CONTROL OF SACCHAROMYCES-CEREVISIAE
POSITIVE REGULATION IN THE GENERAL AMINO-ACID CONTROL OF SACCHAROMYCES-CEREVISIAE
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DOI：
10.1073/pnas.80.17.5374
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发表时间：
1983-01-01
期刊：
影响因子：
--
通讯作者：
FINK, GR
中科院分区：
文献类型：
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作者：
HINNEBUSCH, AG;FINK, GR
酵母菌对单一氨基酸的饥饿导致许多不同氨基酸生物合成途径中的酶的抑制。这种普遍的控制受几个反式作用基因的调控。TRA3基因突变导致结构性去抑制，而AAS基因突变导致不能去抑制。AAS突变被分离出来作为tra3-1突变的抑制者。其中一些抑制子是AAS2的等位基因，另一些则定义了迄今未识别的基因AAS3。研究了同时含有AAS和Tra3突变的菌株和含有克隆的高拷贝数AAS基因的菌株的调控行为。Aas1-或aas2-与tra3组合具有反式表型，而aas3-与tra3组合-具有aas-表型。这些相互作用表明，AAS1和AAS2产物通过禁用TRA3的抑制作用间接地导致去抑制作用，而AAS3产物更直接地发挥作用，即使在缺乏TRA3功能的情况下也是必需的。当存在高拷贝数时，AAS3基因补充AAS1和AAS2的突变，而AAS1和AAS2仅补充其同源突变。综上所述，这些数据表明AAS1和AAS2是TRA3的负调控因子，而TRA3又是AAS3的负调控因子。AAS3是一个正调节器，它是一般控制响应所必需的。这种正负相互作用的模型在形式上与为调节酵母中的半乳糖和磷酸酶系统而提出的模型相同。
Starvation of yeast for a single amino acid leads to depression of enzymes in many different amino acid biosynthetic pathways. This general control is regulated by several trans-acting genes. Mutations in the TRA3 gene result in constitutive derepression, whereas mutations in AAS genes lead to the inability to derepress. aas mutations were isolated as suppressors of the tra3-1 mutation. Some of these suppressors are alleles of AAS2 and others define a heretofore unidentified gene, AAS3. The regulatory behavior of strains containing both aas and tra3 mutations and strains containing the cloned AAS genes in high copy number was studied. Either aas1- or aas2- in combination with tra3- has the Tra- phenotype, whereas aas3- in combination with tra3- has the Aas- phenotype. These interactions suggest that the AAS1 and AAS2 products act indirectly to bring about derepression by disabling the repressive effect of TRA3, whereas the AAS3 product functions more directly and is required even in the absence of the TRA3 function. When present in high copy number, the AAS3 gene complements mutations in AAS1 and AAS2, whereas AAS1 and AAS2 only complement their cognate mutations. Taken together these data suggest that AAS1 and AAS2 are negative regulators of TRA3, which in turn is a negative regulator of AAS3. AAS3 is a positive regulator, which is required for the general control response. This model of negative and positive interactions is formally identical to those proposed for the regulation of the galactose and phosphatase systems in yeast.