作为粗糙脉孢菌亮氨酸生物合成酶产生的调控元件的leu-3顺反子产物。
The product of the leu-3 cistron as a regulatory element for the production of the leucine biosynthetic enzymes of Neurospora.
作者信息
Polacco J C, Gross S R
出版信息
Genetics. 1973 Jul;74(3):443-59. doi: 10.1093/genetics/74.3.443.
A class of intracistronic (or closely linked) partial reversions of leu-3 mutations has been found to be conditionally constitutive with respect to the synthesis of isopropylmalate isomerase (specified by the leu-2 cistron) and beta-isopropylmalate dehydrogenase (specified by the leu-1 cistron), two of the enzymes of leucine biosynthesis in Neurospora. The intermediate level of enzyme production by these leu-3(cc) mutants is independent of the obligatory inducer effector, alpha-isopropylmalate, but dependent upon the presence of the branched-chain amino acids, isoleucine, valine and leucine. The properties of leu-3+, leu-3 and leu-3(cc) in heterokaryons indicate that the transnuclear regulatory activity of the leu-3 product varies specifically as a function of available effector molecules. The information presented suggests that the leu-3 cistron is responsible not only for the production of a "positive" regulatory substance necessary for the expression of the leu-1 and leu-2 cistrons, but that it probably serves also a coordinating role in the expression of many of the genes involved in branched-chain amino acid metabolism.
已发现一类亮氨酸-3（leu-3）突变的顺反子内（或紧密连锁）部分回复突变体，在合成异丁基苹果酸异构酶（由leu-2顺反子编码）和β-异丁基苹果酸脱氢酶（由leu-1顺反子编码）方面呈条件性组成型，这两种酶是粗糙脉孢菌中亮氨酸生物合成的两种酶。这些leu-3（cc）突变体产生的中间水平的酶与必需诱导效应物α-异丁基苹果酸无关，但取决于支链氨基酸异亮氨酸、缬氨酸和亮氨酸的存在。异核体中leu-3 +、leu-3和leu-3（cc）的特性表明，leu-3产物的跨核调节活性根据可用效应分子的功能而有特定变化。所呈现的信息表明，leu-3顺反子不仅负责产生leu-1和leu-2顺反子表达所需的“正向”调节物质，而且它可能在参与支链氨基酸代谢的许多基因的表达中也起协调作用。
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