Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Escherichia coli K-12 produces at least two ATP-dependent proteases, Lon (La) and Clp (Ti), the latter consisting of a regulatory subunit (ClpA) and a proteolytic subunit (ClpP). The gene clpB encoding an analog of ClpA had been found at 57 min on the E. coli chromosome. Cloning and examination of novel heat shock promoters led us to identify a major clpB promoter specifically controlled by a heat shock sigma factor, sigma 32 (the rpoH [= htpR] gene product). beta-Galactosidase synthesis from a PclpB-lacZ operon fusion was transiently induced upon temperature shift from 30 to 42 degrees C, and the induction depended on the rpoH function. Chromosomal clpB transcripts also increased upon temperature upshift and were totally absent in the rpoH deletion strain. In the in vitro transcription experiments, the clpB promoter was specifically recognized and transcribed by RNA polymerase-sigma 32. Nucleotide sequencing and determination of mRNA start sites permitted us to identify a major heat shock promoter located upstream of the clpB coding sequence. The results clearly indicate that clpB expression is under direct control of sigma 32. Since ClpP was recently shown to be a sigma 32-dependent heat shock protein, the present finding suggests the possibility that a potential ATP-dependent protease, ClpB-ClpP complex, plays an important role against thermal stress in E. coli.
...
PMID:Expression of ClpB, an analog of the ATP-dependent protease regulatory subunit in Escherichia coli, is controlled by a heat shock sigma factor (sigma 32). 190 60

Transcription of bacteriophage Mu occurs in a regulatory cascade consisting of three phases: early, middle, and late. The 1.2-kb middle transcript is initiated at Pm and encodes the C protein, the activator of late transcription. A plasmid containing a Pm-lacZ operon fusion was constructed. beta-Galactosidase expression from the plasmid increased 23-fold after Mu prophage induction. Infection of plasmid-containing cells with lambda phages carrying different segment of the Mu early region localized the Pm-lacZ transactivation function to the region containing open reading frames E16 and E17. Deletion and linker insertion analyses of plasmids containing this region identified E17 as the transactivator; therefore we call this gene mor, for middle operon regulator. Expression of mor under the control of a T7 promoter and T7 RNA polymerase resulted in the production of a single polypeptide of 17 kDa as detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Insertion of a linker into mor substantially reduced the ability of Mu to form plaques. When growth of the mor mutant was assayed in liquid, lysis was delayed by about 50 min and the burst size was approximately one-fifth that of wild-type Mu. The mor requirement for plaque formation and normal growth kinetics was abolished when C protein was provided in trans, indicating that the primary function of Mor is to provide sufficient C for late gene expression. Comparison of the predicted amino acid sequence of Mor with other proteins revealed that Mor and C share substantial amino acid sequence homology.
...
PMID:Identification of a positive regulator of the Mu middle operon. 214 78

Bacterial spores are highly resistant to killing by UV radiation and exhibit unique DNA photochemistry. UV irradiation of spore DNA results in formation of spore photoproduct (SP), the thymine dimer 5-thyminyl-5,6-dihydrothymine. Repair of SP occurs during germination of Bacillus subtilis spores by two distinct routes, either by the general nucleotide excision repair (uvr) pathway or by a novel SP-specific monomerization reaction mediated by the enzyme SP lyase, which is encoded by the spl gene. Repair of SP occurs early in spore germination and is independent of de novo protein synthesis, suggesting that the SP repair enzymes are synthesized during sporulation and are packaged in the dormant spore. To test this hypothesis, the expression of a translational spl-lacZ fusion integrated at the spl locus was monitored during B. subtilis growth and sporulation. beta-Galactosidase expression from the spl-lacZ fusion was silent during vegetative growth and was not DNA damage inducible, but it was activated at morphological stage III of sporulation specifically in the forespore compartment, coincident with activation of expression of the stage III marker enzyme glucose dehydrogenase. Expression of the spl-lacZ fusion was shown to be dependent upon the sporulation-specific RNA polymerase containing the sigma-G factor (E sigma G), as spl-lacZ expression was abolished in a mutant harboring a deletion in the sigG gene and restored by expression of the sigG gene in trans. Primer extension analysis of spl mRNA revealed a major extension product initiating upstream from a small open reading frame of unknown function which precedes spl, and it revealed two other shorter minor extension products. All three extension products were present in higher quantities during sporulation and after sigG induction. The three putative transcripts are all preceded by sequences which share homology with the consensus sigma-G factor-type promoter sequence, but in vitro transcription by purified sigma-G RNA polymerase was detected only from the promoter corresponding to the major extension product. The open reading frame-spl operon therefore appears to be an additional member of the sigma-G regulon, which also includes as members the small, acid-soluble spore proteins which are in large part responsible for spore DNA photochemistry. Therefore, sporulating bacteria appear to coordinately regulate genes whose products not only alter spore DNA photochemistry but also repair the major spore-specific photoproduct during germination
...
PMID:Temporal regulation and forespore-specific expression of the spore photoproduct lyase gene by sigma-G RNA polymerase during Bacillus subtilis sporulation. 802 Nov 81

Expression of the Bacillus thuringiensis cryIIIA gene encoding a Coleoptera-specific toxin is weak during vegetative growth and is activated at the onset of the stationary phase. cryIIIA'-'lacZ fusions and primer extension analysis show that the regulation of cryIIIA expression is similar in Bacillus subtilis and in B. thuringiensis. Activation of cryIIIA expression was not altered in B. subtilis mutant strains deficient for the sigma H and sigma E sporulation-specific sigma factors or for minor sigma factors such as sigma B, sigma D, or sigma L. This result and the nucleotide sequence of the -35 and -10 regions of the cryIIIA promoter suggest that cryIIIA expression might be directed by the E sigma A form of RNA polymerase. Expression of the cryIIIA'-'lacZ fusion is shut off after t2 (2 h after time zero) of sporulation in the B. subtilis wild-type strain grown on nutrient broth sporulation medium. However, no decrease in cryIIIA-directed beta-galactosidase activity occurred in sigma H, kinA, or spo0A mutant strains. Moreover, beta-galactosidase activity was higher and remained elevated after t2 in the spo0A mutant strain. beta-Galactosidase activity was weak in abrB and spo0A abrB mutant strains, suggesting that AbrB is responsible for the higher level of cryIIIA expression observed in a spo0A mutant. However, both in spo0A and spo0A abrB mutant strains, beta-galactosidase activity remained elevated after t2, suggesting that even in the absence of AbrB, cryIIIA expression is controlled through modulation of the phosphorylated form of Spo0A. When the cryIIIA gene is expressed in a B. subtilis spo0A mutant strain or in the 168 wild-type strain, large amounts of toxins are produced and accumulate to form a flat rectangular crystal characteristic of the coleopteran-specific B. thuringiensis strains.
...
PMID:Expression in Bacillus subtilis of the Bacillus thuringiensis cryIIIA toxin gene is not dependent on a sporulation-specific sigma factor and is increased in a spo0A mutant. 804 4

The Escherichia coli rhaSR operon encodes two AraC family transcription activators, RhaS and RhaR, and is activated by RhaR in the presence of L-rhamnose. beta-Galactosidase assays of various rhaS-lacZ promoter fusions combined with mobility shift assays indicated that a cyclic AMP receptor protein (CRP) site located at -111.5 is also required for full activation of rhaSR expression. To address the mechanisms of activation by CRP and the RNA polymerase alpha-subunit C-terminal domain (alpha-CTD) at rhaSR, we tested the effects of alanine substitutions in CRP activating regions 1 and 2, overexpression of a truncated version of alpha (alpha-Delta235), and alanine substitutions throughout alpha-CTD. We found that DNA-contacting residues in alpha-CTD are required for full activation, and for simplicity, we discuss alpha-CTD as a third activator of rhaSR. CRP and RhaR could each partially activate transcription in the absence of the other two activators, and alpha-CTD was not capable of activation alone. In the case of CRP, this suggests that this activation involves neither an alpha-CTD interaction nor cooperative binding with RhaR, while in the case of RhaR, this suggests the likelihood of direct interactions with core RNA polymerase. We also found that CRP, RhaR, and alpha-CTD each have synergistic effects on activation by the others, suggesting direct or indirect interactions among all three. We have some evidence that the alpha-CTD-CRP and alpha-CTD-RhaR interactions might be direct. The magnitude of the synergistic effects was usually greater with just two activators than with all three, suggesting possible redundancies in the mechanisms of activation by CRP, alpha-CTD, and RhaR.
...
PMID:Interdependence of activation at rhaSR by cyclic AMP receptor protein, the RNA polymerase alpha subunit C-terminal domain, and rhaR. 1107 23

CrgA is a LysR-type transcriptional regulator involved in the intimate adhesion of Neisseria meningitidis to target human epithelial cells. It is negatively autoregulated, and its expression is transiently induced upon contact with target cells. We analysed the functional organization of CrgA using in frame deleted proteins. Four truncated proteins were constructed and purified. They were deleted between residues 20 and 40, 121 and 154, 111 and 181 and 268 and 291. Meningococcal mutants harbouring the corresponding deleted crgA alleles were also constructed. All mutants showed a reduced ability to adhere to epithelial cells. beta-Galactosidase activity assays using a crgA-lacZ transcriptional fusion showed that all the mutations except the 268-291 deletion resulted in loss of induction upon contact with target cells. Gel mobility shift assays and cross-linking assays showed that the oligomerization of CrgA is required for DNA binding and that the N-terminal part of CrgA is directly involved in DNA binding through a helix-turn-helix motif. The C-terminal region is also involved in DNA binding, probably by permitting the oligomerization of CrgA. The C-terminal region also seemed to interact with RNA polymerase. Therefore, the binding of CrgA and its interaction with RNA polymerase may inhibit the clearance of meningococcal promoters that are repressed by CrgA during the intimate adhesion of N. meningitidis to target cells.
...
PMID:The Neisseria meningitidis adhesion regulatory protein CrgA acts through oligomerization and interaction with RNA polymerase. 1249 59

A cluster of genes coding for putative plant cell-wall degrading enzymes (i.e., genes for two endoglucanases [gunA and gunA2], one pectinmethylesterase [pme], and one polygalacturonase [pgl]) was identified by sequence similarities in the symbiotic region of the Bradyrhizobium japonicum chromosome. In addition, a systematic screen of the region revealed several genes potentially transcribed by the sigma(54)-RNA polymerase and activated by the transcriptional regulator NifA (i.e., genes for proteins with similarity to outer membrane proteins [id117 and id525] and a citrate carrier [id331 or citA] and one open reading frame without similarity to known proteins [id747]). Expression studies using transcriptional lacZ fusions showed that gunA2 and pgl were strongly induced by the isoflavone genistein in a NodW-dependent manner, suggesting a role of the gene products in early events of the nodulation process; by contrast, gunA and pme expression was very weak in the conditions tested. The gunA2 gene product was purified and was shown to have cellulase activity. beta-Galactosidase activity expressed from transcriptional lacZ fusions to id117, id525, and id747 in the wild type and in nifA and rpoN mutant backgrounds confirmed that their transcription was dependent on NifA and sigma(54). Despite the presence of a -24/-12-type promoter and a NifA binding site upstream of citA, no regulation could be demonstrated in this case. Null mutations introduced in gunA, gunA2, pgl, pme, citA, id117, id525, and id747 did not impair the symbiosis with the host plants.
...
PMID:New NodW- or NifA-regulated Bradyrhizobium japonicum genes. 1274 63

---