Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A plasmid vector containing a multiple-cloning site followed by a promoterless chloramphenicol acetyltransferase (cat) gene, protected by transcription terminators and mobilizable by conjugation from Escherichia coli into Anabaena sp. strain PCC 7120, was constructed. The utility of the vector was shown by deletion analysis of the promoter region of the Anabaena psbB gene.
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PMID:A vector for analysis of promoters in the cyanobacterium Anabaena sp. strain PCC 7120. 190 75

A new glutamine synthetase gene, glnN, which encodes a polypeptide of 724 amino acid residues (M(r), 79,416), has been identified in the unicellular cyanobacterium Synechocystis sp. strain PCC 6803; this is the second gene that encodes a glutamine synthetase (GS) in this cyanobacterium. The functionality of this gene was evidenced by its ability to complement an Escherichia coli glnA mutant and to support Synechocystis growth in a strain whose glnA gene was inactivated by insertional mutagenesis. In this mutant (strain SJCR3), as well as in the wild-type strain, the second GS activity was subject to regulation by the nitrogen source, being strongly enhanced in nitrogen-free medium. Transcriptional fusion of a chloramphenicol acetyltransferase (cat) gene with the 5'-upstream region of glnN suggested that synthesis of the second Synechocystis GS is regulated at the transcriptional level. Furthermore, the level of glnN mRNA, a transcript of about 2,300 bases, was found to be strongly increased in nitrogen-free medium. The glnN product is similar to the GS subunits of Bacteroides fragilis and Butyrivibrio fibrisolvens, two obligate anaerobic bacteria whose GSs are markedly different from other prokaryotic and eukaryotic GSs. However, significant similarity is evident in the five regions which are homologous in all of the GSs so far described. The new GS gene was also found in other cyanobacteria but not in N2-fixing filamentous species.
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PMID:A new type of glutamine synthetase in cyanobacteria: the protein encoded by the glnN gene supports nitrogen assimilation in Synechocystis sp. strain PCC 6803. 790 87

Proteins of cyanobacteria may be transported across one of two membrane systems: the typical eubacterial cell envelope (consisting of an inner membrane, periplasmic space, and an outer membrane) and the photosynthetic thylakoids. To investigate the role of signal peptides in targeting in cyanobacteria, Synechococcus sp. strain PCC 7942 was transformed with vectors carrying the chloramphenicol acetyltransferase reporter gene fused to coding sequences for one of four different signal peptides. These included signal peptides of two proteins of periplasmic space origin (one from Escherichia coli and the other from Synechococcus sp. strain PCC 7942) and two other signal peptides of proteins located in the thylakoid lumen (one from a cyanobacterium and the other from a higher plant). The location of the gene fusion products expressed in Synechococcus sp. strain PCC 7942 was determined by a chloramphenicol acetyltransferase enzyme-linked immunosorbent assay of subcellular fractions. The distribution pattern for gene fusions with periplasmic signal peptides was different from that of gene fusions with thylakoid lumen signal peptides. Primary sequence analysis revealed conserved features in the thylakoid lumen signal peptides that were absent from the periplasmic signal peptides. These results suggest the importance of the signal peptide in protein targeting in cyanobacteria and point to the presence of signal peptide features conserved between chloroplasts and cyanobacteria for targeting of proteins to the thylakoid lumen.
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PMID:Role of signal peptides in targeting of proteins in cyanobacteria. 814 51

A homologue of the 'ferric uptake regulation' gene (fur) was isolated from the cyanobacterium Synechococcus sp. strain PCC 7942 by an Escherichia coli-based 'in vivo repression assay'. The assay uses a reporter-gene construct containing the promoter region of the iron-regulated cyanobacterial gene isiA, fused to the coding region for chloramphenicol acetyltransferase. The isolated gene codes for a protein that has 41% sequence similarity (36% identity) to Fur from E. coli and contains the putative iron-binding motif found in the Fur proteins of purple bacteria. No significant similarity was found to the DxtR repressor that regulates the expression of toxin and siderophore production in Gram-positive bacteria. Insertional mutagenesis of the cloned cyanobacterial fur gene led to the creation of heteroallelic mutants that showed iron-deficiency symptoms in iron-replete medium, including the constitutive production of flavodoxin and of hydroxamate siderophores. Failure to eliminate wild-type copies of the fur gene from the polyploid genome of Synechococcus 7942 implies that in this cyanobacterium Fur may have essential functions in addition to the regulation of genes involved in iron scavenging or photosynthetic electron transport.
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PMID:Fur regulates the expression of iron-stress genes in the cyanobacterium Synechococcus sp. strain PCC 7942. 870 86

A new insertion sequence element, IS1452, was found to be associated with inactivation of the alcohol dehydrogenase by insertion in the adhS gene encoding subunit III of the three-component membrane-bound alcohol dehydrogenase complex in Acetobacter pasteurianus. Cloning and sequencing analyses of the mutated subunit III gene locus revealed that IS1452 was inserted at or near the ribosome-binding sequence of adhS. Analysis of transcription using the chloramphenicol acetyltransferase gene as the reporter indicated that IS1452 abolished transcription of adhS by separating its promoter from the subunit III structural gene. IS1452 was 1411 bp in length and had a terminal inverted repeat of 21 bp. IS1452 contained one long ORF of 416 amino acids rich in basic amino acids. This protein showed homology with a putative transposes, Tra1, of IS701 isolated from the cyanobacterium Calothrix species PCC 7601. Like IS701, IS1452 was found to generate a 4 bp direct repeat at the site of insertion upon transposition. The target site specificity was rather strict, and a CTA(A or G) sequence appeared to be preferentially recognized. Transposition of IS1452 was replicative, since it was accompanied by an increase in the copy number of IS1452. Several strains belonging to the genus Acetobacter also contained IS1452 at varying copy numbers from one to more than ten. These observations suggest that IS1452 is one of the insertion sequences that are responsible for genetic instability leading to deficiencies in various physiological properties in acetic acid bacteria.
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PMID:A new insertion sequence IS1452 from Acetobacter pasteurianus. 904 30

The in vivo promoter activity of the 5'-region of the genes encoding the carotenogenic enzymes phytoene desaturase (crtP) and phytoene synthase (crtB) from the cyanobacterium Synechocystis sp. PCC 6803 has been studied by deletion mapping, primer extension, Northern blot, and using the chloramphenicol acetyltransferase (cat) reporter gene. crtP and crtB are closely linked in the Synechocystis genome, but it is shown that both genes are independently transcribed. The level of transcription in both cases is very low. Their expression is affected in a similar way by light intensity: very little or no expression is observed in the dark compared with expression under illumination conditions. High light intensities induce a transient increase in transcription initiation as detected with the cat probe. DNA fragments containing 81 base pairs upstream of the crtP putative transcription initiation site or 192 base pairs upstream of the crtB putative transcription initiation site are enough to confer light sensitive expression to a reporter gene.
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PMID:Characterization of two carotenoid gene promoters in the cyanobacterium Synechocystis sp. PCC 6803. 987 19

Cyanobacterial natural products offer new possibilities for drugs and lead compounds but many factors can inhibit the production of sufficient yields for pharmaceutical processes. While Escherichia coli and Streptomyces sp. have been used as heterologous expression hosts to produce cyanobacterial natural products, they have not met with resounding success largely due to their inability to recognize cyanobacterial promoter regions. Recent work has shown that the filamentous freshwater cyanobacterium Anabaena sp. strain PCC 7120 recognizes various cyanobacterial promoter regions and can produce lyngbyatoxin A from the native promoter. Introduction of Anabaena sigma factors into E. coli might allow the native transcriptional machinery to recognize cyanobacterial promoters. Here, all 12 Anabaena sigma factors were expressed in E. coli and subsets were found to initiate transcription from several cyanobacterial promoters based on transcriptional fusions to the chloramphenicol acetyltransferase (CAT) reporter. Expression of individual Anabaena sigma factors in E. coli did not result in lyngbyatoxin A production from its native cyanobacterial gene cluster, possibly hindered by deficiencies in recognition of cyanobacterial ribosomal binding sites by native E. coli translational machinery. This represents an important step toward engineering E. coli into a general heterologous expression host for cyanobacterial biosynthetic gene cluster expression.
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PMID:The influence of sigma factors and ribosomal recognition elements on heterologous expression of cyanobacterial gene clusters in Escherichia coli. 2998 30