A genetic analysis of the pteridine biosynthetic enzyme, guanosine triphosphate cyclohydrolase, in Drosophila melanogaster.
A genetic analysis of the pteridine biosynthetic enzyme, guanosine triphosphate cyclohydrolase, in Drosophila melanogaster.
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DOI：
10.1093/genetics/105.1.35
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发表时间：
1983-09
期刊：
影响因子：
3.3
通讯作者：
W. Mackay;J. O'donnell
中科院分区：
文献类型：
--
作者：
W. Mackay;J. O'donnell
对眼睛颜色突变的菌株进行了GTP环化水解酶（GTP CH）水平的调查，GTP CH是在蝶啶生物合成中起作用的第一种酶，蝶啶是导致果蝇眼睛颜色变红的色素。发现六个菌株具有降低的GTP CH活性。在六个菌株中的五个中，活性的降低仅在纯合突变体的成年头部中是明显的。我们发现，在冲床（2-97，钚）突变有严重的影响GTP CH活性。在大多数情况下，活性的降低在表达酶的所有组织和阶段中是明显的。GTP CH的活性与基因组中Pu+基因的数量密切相关。甲磺酸乙酯（EMS）诱导的Pu突变体的GTP CH酶是不稳定的，与野生型酶相比。Pu的突变分为三大类。最大的一类具有隐性致死和眼睛颜色表型，在杂合子中具有50%或更高的GTP CH活性，并且在所有组织中具有等同的缺陷。第二类是显性的眼睛颜色表型和隐性致死，与小于50%的GTP CH活性杂合子。第三类是纯合子活的，在成年头部有严重的活性降低，但在其他组织中没有或不太严重的损失。
Strains with mutant eye color were surveyed for levels of GTP cyclohydrolase (GTP CH), the first enzyme acting in the biosynthesis of pteridines, the pigments causing red eye color in Drosophila. Six strains were found to have reduced GTP CH activity. In five of the six strains, the reduction of activity is apparent only in the adult head of homozygous mutants. We show that mutations in Punch (2-97, Pu) have severe effects on GTP CH activity. In most cases, the reduction of activity is apparent in all tissues and stages that express the enzyme. The activity of GTP CH is shown to be closely correlated with the number of Pu+ genes in the genome. One ethyl methanesulfonate (EMS)-induced Pu mutant has a GTP CH enzyme that is unstable when compared with the wild-type enzyme. Mutations in Pu fall into three general classes. The largest class has a recessive lethal and eye color phenotype, 50% or higher GTP CH activity in heterozygotes, and equivalent defects in all tissues. A second class is dominant in eye color phenotype and recessive lethal, with less than 50% GTP CH activity in heterozygotes. The third class is homozygous viable and has severe reduction of activity in the adult head, but no or less severe loss in other tissues.