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)

The cIII gene product of lambdoid bacteriophages promotes lysogeny by stabilizing the phage-encoded CII protein, a transcriptional activator of the repressor and integrase genes. Previous works showed that the synthesis of the bacteriophage lambda CIII protein has specific translational requirements imposed by the structure of the mRNA. To gain insight into the mRNA structure and its role in regulating cIII translation, we undertook a mutational analysis of the cIII gene of the related bacteriophage HK022. Our data support the hypothesis that in HK022, as in lambda, translation initiation requires a specific mRNA structure. In addition, we found that translation of HK022 cIII, like that of lambda, is strongly reduced in a host deficient in the endonuclease RNase III.
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PMID:Genetic analysis of the cIII gene of bacteriophage HK022. 182 68

The bacteriophage lambda int gene product, integrase, recombines the phage DNA with the host DNA at specific sites on each to accomplish lysogeny. The int gene is transcribed from two promoters, PL and PI, each regulated positively by lambda proteins. The expression of integrase is also controlled from a site, sib, in the b region of the phage genome. This is a unique regulatory site because it is located distal to the structural gene in relation to the promoters. The expression of int from the PL promoter is inhibited when sib is present. This effect appears to be specific for PL because sib does not cause inhibition of PI-dependent int synthesis. lambda mutants that contain alterations in the site have been isolated. Sequence analyses of the mutations reveal single base changes, spanning 37 base pairs (bp) in the b region, some 240 bp beyond the int gene. Another mutant, hef13, which has a phenotype similar to that of sib, introduces a nucleotide change within the same 37-bp region. The sib and hef mutations cluster within a region of dyad symmetry. Regulation of int synthesis by sib occurs after transcription of the int gene. There is no difference in the rate of PL-promoted int mRNA synthesis in either sib+ or sib- phage infections, yet int mRNA is less stable in the sib+ infection. Because RNase III host mutants are defective in sib regulation, processing of the PL mRNA at sib by this endoribonuclease may cause int mRNA decay and decrease int synthesis.
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PMID:Posttranscriptional control of bacteriophage lambda gene expression from a site distal to the gene. 628 59

The lambda int gene product, integrase, recombines phage and bacterial DNA at a specific site during the integration step of lysogeny. Regulation of integrase synthesis is complex. (1) Transcription of the gene can occur from either of two promoters. lambda cII protein activates transcription initiation near int at pI. The lambda N protein allows transcription of int from pL. N protein acts by preventing transcription termination at several terminators between pL and int. (2) The expression of integrase is also subject to post-transcriptional regulation by a site, sib, which is located beyond int in the b region of lambda. Expression of int from pL is inhibited by sib, whereas that from pI is not. The negative control of int expression by sib is termed retroregulation. Retroregulation of int is caused, in part, by processing of the pL transcript at the sib site by RNase III of Escherichia coli. The exonuclease, Bal31, was used to generate a set of deletions to define the sib regulatory site. Both sib+ and sib- deletions were sequenced, and it was concluded from this and other work that a dyad symmetry present in the b region, 270 base-pairs from int, was necessary for retroregulation. The RNA structure of this segment is similar to other RNase III-sensitive sites found in E. coli and phage RNAs.
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PMID:Deletion analysis of the retroregulatory site for the lambda int gene. 630 22