Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.3 (RNase III)
 1,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transcripts from the rplKAJL-rpoBC ribosomal protein-RNA polymerase gene cluster have been quantified and their ends mapped using RNA-DNA hybridization, sucrose density-gradient sedimentation, Northern hybridization and S1 nuclease protection. The results indicate that the most abundant transcript is the 2600 nucleotide tetracistronic L11-L1-L10-L12 mRNA initiated at the upstream major PL11 promoter and terminated at the transcription attenuator in the L12-beta intergenic space. Somewhat less abundant 1300 nucleotide L11-L1 and L10-L12 bicistronic transcripts were observed. The 3' ends of the L11-L1 transcripts were heterogeneous; most of the ends were localized to three sites within a 110 base-pair region in the L1-L10 intergenic space. This intergenic space encodes also the major PL10 promoter and the mRNA binding site for the L10 translational control protein. Two 5' ends were observed for L10-L12 bicistronic mRNA, one at the PL10 promoter and the other 150 nucleotides further downstream in a region in which promoter activity has not been detected. It is suggested that this second downstream 5' end is generated by processing of the transcripts initiated at the major PL10 promoter. No transcript initiation in the L10-L12 intergenic space was detected. About 80% of the transcripts reading through the L12 gene were terminated in the vicinity of the transcription attenuator that is responsible for the reduction in the expression of the downstream RNA polymerase genes. Transcripts reading through the attenuator were partially processed by RNase III within a potential hairpin structure in the RNA transcript. Processing appears to produce 3' and 5' transcript end sites separated by about ten nucleotides. No other major 5' ends were observed in the L12-beta intergenic space. These results indicate that the two major promoters, PL11 and PL10, are both utilized to drive the interrelated transcriptional expression of this ribosomal protein-RNA polymerase gene cluster.
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PMID:Transcription products from the rplKAJL-rpoBC gene cluster. 244 6

Transiently stable products derived from the endonuclease cleavage of transcripts from the secEnusG and rplKAJLrpoBC operons have been identified. Cleavage sites for RNase III occur in the leader of the secEnusG transcript and in the L12-beta intercistronic space of the rplKAJLrpoBC transcript. A single RNase E cleavage site was located in the L1-L10 intergenic space. Inactivation of RNase III and RNase E results respectively in a one- to twofold and a greater than 10-fold stabilization of five mRNA sequences from within the secE, nusG, L11-L1, L10 and beta encoding cistrons. The relative amounts of each of these five mRNA sequences were found to be nearly constant when measured either in the presence or absence of cleavage by RNase III or RNase E. This clearly implies that any increases in the stability of these mRNA sequences resulting from the inactivation of processing by RNase III or RNAase E are counterbalanced by changes in the mRNA synthesis rates. The mechanism that links mRNA synthesis to mRNA decay is not known.
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PMID:Coupling between mRNA synthesis and mRNA stability in Escherichia coli. 751 86