micF RNA binds to the 5' end of ompF mRNA and to a protein from Escherichia coli.
micF RNA regulates the levels of outer membrane protein F (OmpF) in Escherichia coli in response to temperature increase and other stress conditions by decreasing the levels of ompF mRNA (Andersen et al., 1989). A 93-nucleotide micF RNA was synthesized in vitro directly from polymerase chain reaction generated DNA which was designed to contain a functional T7 RNA polymerase promoter upstream of the micF RNA gene and an appropriate restriction site for transcription termination. A transcript (150 nucleotides) containing the ribosomal binding domain of ompF mRNA messenger was synthesized in vitro from the ompF gene cloned into a T7 expression vector. A stable duplex was formed between micF RNA and the 150-nucleotide 5' transcript of ompF mRNA after incubation at 37 degrees C in a physiological buffer. The melting curve of the duplex formed by micF RNA and 150-nucleotide transcript revealed a Tm of 56 degrees C and a delta Tm that spans about 20 degrees C; both are consistent with the proposed structure for the micF/ompF duplex. In addition, as determined by competition studies and UV cross-linking/label-transfer analyses, an E. coli protein was found to bind specifically to micF RNA. The protein also bound weakly to the 150-nucleotide ompF transcript. The data are the first to demonstrate the complex between micF RNA and the 5' end of ompF mRNA and suggest that in vivo a micF ribonucleoprotein (RNP) particle may participate in the destabilization ompF mRNA during thermoregulation of OmpF porin.
Andersen
J
J
Department of Microbiology, School of Medicine, State University of New York, Stony Brook 11794.
Delihas
N
N
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000235:genetics; D013696:Temperature; D014158:Transcription, Genetic; D014764:Viral Proteins
D001425:Bacterial Outer Membrane Proteins; D012329:RNA, Bacterial; D012261:Ribonucleoproteins; D014764:Viral Proteins; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases