Disease relevance of ISOPROPYL THIOGALACTOSIDE

• The crystal structure of the tryptic core fragment of the lac repressor of Escherichia coli (LacR) complexed with the inducer isopropyl-beta-D-thiogalactoside was determined at 2.6 A resolution [1].
• A Bacillus subtilis strain was constructed in which the cell division gene, ftsZ, was placed under control of the isopropyl-beta-D-thiogalactoside (IPTG)-inducible spac promoter [2].
• Infection of Escherichia coli with these phage followed by induction of the lac promoter with isopropyl thiogalactoside gives high yields (up to 10(9) units/liter with an average of 1.5 X 10(8) units/liter) of the modified IFN-alpha 2 [3].
• When placed downstream of the tac promoter in the broad-host-range plasmid pMMB22, this fragment directs the synthesis of all three enzymes in both E. coli and Pseudomonas putida only on induction with isopropyl beta-D-thiogalactopyranoside, suggesting that the gene cluster is regulated as a single unit under the control of a single promoter [4].
• The expression of the Rhizobium meliloti glutamyl-tRNA synthetase gene in Escherichia coli under the control of a trc promoter results in a toxic effect upon isopropyl-beta-D-thiogalactopyranoside induction, which is probably caused by a misacylation activity [5].

High impact information on ISOPROPYL THIOGALACTOSIDE

• For the toggle switch, LacI was provided constitutively; the level of active repressor was controlled by using a lacY mutant and varying the concentration of IPTG [6].
• At 42 degrees C, initiation of DNA replication was totally dependent upon the gratuitous inducer isopropyl beta-D-thiogalactopyranoside (IPTG) [7].
• When grown in medium containing isopropyl beta-D-thiogalactoside (IPTG), these cells acquired a CAT+ phenotype [8].
• In vitro, early transcription from pSVlacO, but not from pX-8, was inhibited by lac repressor, and repression was overcome by IPTG [9].
• Pigmentation of the mouse was controlled by the interaction of the lac repressor with the regulatable Tyrosinase transgene in a manner that was fully reversible by the lactose analog IPTG [10].

Chemical compound and disease context of ISOPROPYL THIOGALACTOSIDE

• The three E. coli JM109 strains harboring the plasmids pDTG601, pDTG602, and pDTG603, after induction with isopropyl-beta-D-thiogalactopyranoside, oxidized toluene to (+)-cis-(1S, 2R)-dihydroxy-3-methylcyclohexa-3,5-diene, 3-methylcatechol, and 2-hydroxy-6-oxo-2,4-heptadienoate, respectively [11].
• Expression of the lactose operon upon induction by IPTG was studied with Escherichia coli B/r and K-12 strains as a function of exposure to ultraviolet light [12].
• This hybrid gene conferred hygromycin resistance to E. coli, and expression of resistance was under IPTG control [13].
• For most of the variants studied, the yield of protein was significantly enhanced by growth at 28 degrees C and inclusion of sucrose and betaine, in addition to isopropyl-beta-d-thiogalactoside (IPTG), to the growth medium of the E. coli expression host [14].
• Rabbit lung prostaglandin omega-hydroxylase (P450 4A4) was expressed in Escherichia coli using the isopropyl beta-D-thiogalactopyranoside (IPTG) inducible expression vector pCWori+, containing the full-length cDNA encoding the P450 4A4 [15].

Biological context of ISOPROPYL THIOGALACTOSIDE

• This effect is not observed in cells lacking repressor or in the absence of the operator, and it is reversed by an inducer of the lac operon, namely isopropyl thiogalactoside (IPTG) [16].
• IPTG-induced C/EBPalpha caused inhibition of cell proliferation and DNA synthesis as measured by colony growth assays, cell counting, and BrdU uptake [17].
• When such plasmids are placed into an E. coli strain containing a chromosomal copy of the gene for T7 RNA polymerase under control of the lac UV5 promoter, high-level synthesis of rRNAs from the plasmid can be induced by adding IPTG to exponentially growing cells [18].
• An E.coli strain possessing chromosomal hemM under the control of the lac promoter-operator required IPTG for growth, indicating that hemM (lolB) is an essential gene [19].
• Here, we used accurate gene expression measurements from living cell cultures, bearing GFP reporters, to map in detail the input function of the classic lacZYA operon of Escherichia coli, as a function of about a hundred combinations of its two inducers, cAMP and isopropyl beta-d-thiogalactoside (IPTG) [20].

Anatomical context of ISOPROPYL THIOGALACTOSIDE

• In lacI protoplasts the presence of IPTG manifested itself in a 4.2-fold relief of repression [21].
• A cell line that stably carries both the lacI and lacZ genes was efficiently induced to synthesize beta-galactosidase after isopropyl beta-D-thiogalactoside administration [22].
• To distinguish between these possibilities, primary rat embryo fibroblasts were transformed with mutant p53 plus ras cDNAs, where the expression of the p53 gene was regulated by an isopropyl beta-D-thiogalactoside-responsive promoter [23].
• To express these constructs, L8 myoblast cell lines were transfected with LacSwitch plasmids, which allowed for isopropyl beta-D-thiogalactoside-dependent expression of the gene of interest [24].
• When MARCO was expressed in HL-60 cells with the lac switch system, blastic cell morphology became neutrophilic after 48-hour incubation with IPTG, and cell death was observed after 3 days [25].

Associations of ISOPROPYL THIOGALACTOSIDE with other chemical compounds

• In medium containing methotrexate but no IPTG, the clones were unable to grow in soft agar, indicating that methotrexate resistance due to gene amplification is separable from transformation [26].
• Following transcriptional induction with IPTG or galactose, subcellular fractions were prepared and analyzed immunochemically and catalytically [27].
• In the absence of an inducer (allolactose or IPTG) this strain, DH1 lackan , cannot grow on kanamycin-containing media due to the repression of kan expression by LacI protein binding to lac O/P [28].
• Nutrient starvation experiments and the use of relA spoT mutant strains, IPTG-regulated overproduction of ppGpp and lacZ fusions revealed that the stringent response alarmone guanosine 3',5'-bispyrophosphate (ppGpp) is the main positive effector of Cka synthesis [29].
• In contrast, in these cells, IPTG-dependent induction of p14ARF, which sequesters MDM2 away from p53, does not lead to detectable phosphorylation of any of the five N-terminal serine residues tested (6, 9, 15, 20, 37) [30].

Gene context of ISOPROPYL THIOGALACTOSIDE

• To confirm that these aberrations occurred within the first cell cycle after mutant Ha-ras induction, the cells were arrested in G1 phase by serum depletion and, subsequently, released by administration of isopropyl beta-D-thiogalactoside or serum [31].
• Production of cAMP in the transformant carrying CYR1 and either RAS2 or RAS2val19 was confirmed by staining colonies on maltose-MacConkey plates and by measuring induction of beta-galactosidase by isopropyl beta-D-thiogalactopyranoside [32].
• Synthesis or repression of Fos in L1-3c-fos cells occurred rapidly, within 30 min, after the removal or addition of IPTG to the culture medium [33].
• Also, the conditional IPTG inducible expression of wild type Sgk, but not of the kinase dead T256A mutant Sgk, protected Con8 mammary epithelial tumor cells from serum starvation-induced apoptosis [34].
• We have expressed human tryptophan hydroxylase 2 (hTPH2) and two deletion mutants (NDelta150 and NDelta150/CDelta24) using isopropyl beta-d-thiogalactopyranoside-free autoinduction in Escherichia coli [35].

Analytical, diagnostic and therapeutic context of ISOPROPYL THIOGALACTOSIDE

• The mitoses from cells released with isopropyl beta-D-thiogalactoside contained a 3-fold elevation in the fraction of chromosomes containing aberrations compared to mitoses from parallel cell cultures that were released with serum [31].
• Upon removal of isopropyl- beta-D-thiogalactoside chick occludin expression declined slowly until it was no longer detected in western blots 72 hours later; transepithelial electrical resistance also returned to baseline values during this time [36].
• Active cells were enumerated by fluorescence microscopy after treatment with the lac inducer IPTG and cytological assay for beta-galactosidase [37].
• Electron microscopy of cells infected in the absence of IPTG revealed normal-appearing crescents and immature virus particles but very few with nucleoids [38].
• Further studies indicated that the yield of infectious virus could be regulated by titration with IPTG and that virus production was arrested by IPTG removal at appropriate times [39].

References