|Related Categories||Core Bioreagents, Featured Products, Gene Reporter Substrates, General Reagents, Life Science Reagents for Cloning,|
|grade||for molecular biology|
|usage||sufficient for 125 dishes (90 mm)|
|shipped in||dry ice|
40 mg/mL IPTG
40 mg/mL X-Gal
(prepared in DMSO)
• Intense color contrast for easy colony selection
• Convenient, ready-to-use solution
Sigma’s Blue-White Select™ Screening Reagent is a chromogenic substrate for β-galactosidase, used to determine the presence or absence of a cloned DNA insert in bacteria growing on agar plates. Blue-White Select™ Screening Reagent is designed for blue-white selection of recombinant bacterial colonies with the lac+ phenotype.
When Blue-White Select™ Screening Reagent is cleaved by β-galactosidase, the resulting product will form a blue precipitate. Lac+ colonies grown in the presence of Blue-White Select™ Screening Reagent remain white in color, allowing for easy differentiation between lac+ and lac- colonies.
The technique is based on vectors such as the pUC and the M13mp series that carry a fragment of the β-galactosidase gene encoding an a-fragment of β-galactosidase. Exploitation of these vectors requires use of a bacteria strain carrying the complementing gene fragment to allow the assembly of an active complex, resulting in the formation of blue colonies. Disruption of the ß-galactosidase gene by insertion of a DNA fragment into the vector′s multiple cloning site results in the loss of functional β-galactosidase activity; these colonies remain white, allowing for easy differentiation between lac+ and lac- colonies.
Blue-White Select is a trademark of Sigma-Aldrich Co. LLC
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|Personal Protective Equipment||Eyeshields, full-face respirator (US), Gloves, multi-purpose combination respirator cartridge (US), type ABEK (EN14387) respirator filter|
Ausubel, F.M., et al. Curr. Protoc. Mol. Biol. New York, NY , (1995), 1.4.1, 1.4.5, 1.5.5
Characterization by in vitro complementation of a peptide corresponding to an operator-proximal segment of the β-galactosidase structural gene of Escherichia coli.. Ullmann, A., et al. J. Mol. Biol. 24, 339, (1967)
Regulation of the Escherichia coli lac operon expressed in human cells. Bioard, D.S. et al. Biochim. Biophys. Acta 113, 68-74, (1992)
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