Stauffer Lorraine T, Stauffer George V
Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA.
ISRN Microbiol. 2012 May 28;2012:636273. doi: 10.5402/2012/636273. Print 2012.
The Escherichia coli sRNA GcvB regulates several genes involved in transport of amino acids and peptides (sstT, oppA, dppA, and cycA). Two regions of GcvB from nt +124 to +161 and from nt +73 to +82 are complementary with essentially the same region of the cycA mRNA. Transcriptional fusions of cycA to lacZ showed the region of cycA mRNA that can pair with either region of GcvB is necessary for regulation by GcvB. However, mutations in either region of gcvB predicted to disrupt pairing between cycA mRNA and GcvB did not alter expression of a cycA-lacZ translational fusion. A genetic analysis identified nts in GcvB necessary for regulation of the cycA-lacZ fusion. The results show that either region of GcvB complementary to cycA mRNA can basepair with and independently repress cycA-lacZ and both regions need to be changed to cause a significant loss of repression.
大肠杆菌小RNA GcvB调控多个参与氨基酸和肽转运的基因（sstT、oppA、dppA和cycA）。GcvB从核苷酸+124到+161以及从核苷酸+73到+82的两个区域与cycA mRNA的基本相同区域互补。cycA与lacZ的转录融合表明，cycA mRNA中可与GcvB任一区域配对的区域对于GcvB的调控是必需的。然而，预测会破坏cycA mRNA与GcvB之间配对的gcvB任一区域的突变并未改变cycA-lacZ翻译融合体的表达。遗传分析确定了GcvB中调控cycA-lacZ融合所必需的核苷酸。结果表明，GcvB与cycA mRNA互补的任一区域均可与cycA-lacZ碱基配对并独立抑制其表达，且两个区域都需要改变才能导致显著的抑制作用丧失。
