Liang J, Scappino L, Haselkorn R
Department of Molecular Genetics and Cell Biology, University of Chicago, IL 60637.
Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5655-9. doi: 10.1073/pnas.89.12.5655.
In Anabaena 7120, heterocysts (cells specialized for nitrogen fixation) develop at the ends of filaments and at intervals within each filament. We have isolated a mutant Anabaena strain that develops heterocysts mostly at the ends of filaments. This mutant, PAT-1, grows poorly under nitrogen-fixing conditions. The wild-type gene that complements the mutation in PAT-1, called patA, was cloned and sequenced. The predicted PatA protein contains 379 amino acids distributed among three "domains" based on predictions of hydropathy and flexibility. The carboxyl-terminal domain is very similar to that of CheY and other response regulators in two-component regulatory systems in eubacteria. The patA mutation suppresses the multiheterocyst phenotype produced by extra copies of the wild-type hetR gene described previously, suggesting that PatA and HetR are components of the same environment-sensing regulatory circuit in Anabaena.
在鱼腥藻7120中，异形胞（专门用于固氮的细胞）在丝状体的末端以及每条丝状体内部的间隔处形成。我们分离出了一种突变的鱼腥藻菌株，该菌株的异形胞大多在丝状体的末端形成。这种突变体PAT-1在固氮条件下生长不良。对与PAT-1中的突变互补的野生型基因（称为patA）进行了克隆和测序。根据亲水性和柔韧性预测，预测的PatA蛋白含有379个氨基酸，分布在三个“结构域”中。羧基末端结构域与真细菌双组分调节系统中的CheY和其他应答调节因子的结构域非常相似。patA突变抑制了先前描述的野生型hetR基因额外拷贝产生的多异形胞表型，这表明PatA和HetR是鱼腥藻中同一环境感知调节回路的组成部分。
