Salinas P C, Crosa J H
Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland 97201, USA.
Gene. 1995 Jul 4;160(1):17-23. doi: 10.1016/0378-1119(95)00213-p.
AngR and the product(s) encoded in the trans-acting factor (TAF) region are necessary for the full expression of the pJM1 plasmid-mediated anguibactin iron-uptake system in Vibrio anguillarum (Va). In this report, we analyzed the factors that affect the expression of the angR gene. Northern blot analysis showed that angR encodes a 3.1-kb transcript which is expressed only under iron-limiting conditions. Measurement of steady-state RNA levels show that, under iron-limiting conditions, angR is positively regulated at the transcriptional level by product(s) of the Va TAF region. However, this enhancement of angR expression by TAF does not occur at high levels of the AngR protein, as assessed by using an angR::lacZ fusion in the presence of a construct containing angR under the control of ptac. We also report that repression of angR by iron could possibly be mediated by an endogenous Va antisense RNA beta, which contains a stem-loop structure complementary to the stem-loop structure located at the 5' end of angR.
血管紧张素受体（AngR）和反式作用因子（TAF）区域编码的产物对于鳗弧菌（Va）中pJM1质粒介导的鳗弧菌素铁摄取系统的完整表达是必需的。在本报告中，我们分析了影响angR基因表达的因素。Northern印迹分析表明，angR编码一个3.1 kb的转录本，该转录本仅在铁限制条件下表达。稳态RNA水平的测量表明，在铁限制条件下，angR在转录水平上受到Va TAF区域产物的正向调控。然而，通过在ptac控制下使用含有angR的构建体存在时的angR::lacZ融合来评估，当AngR蛋白水平较高时，TAF对angR表达的这种增强作用不会发生。我们还报告说，铁对angR的抑制可能是由内源性Va反义RNAβ介导的，该反义RNAβ含有与位于angR 5'端的茎环结构互补的茎环结构。
