title: Multiplex detection and quantitation of proteins on western blots using fluorescent probes.
abstract: The uses of multiplex detection methodologies are dramatically increasing as a means to increase sample throughput and to demonstrate quantitative differences between multiple targets in gene or protein expression analysis. In this study, we investigate the application of multiplex fluorescent detection for three proteins on the same Western blot using a laser-scanning imaging system, the Bio-Rad Molecular Imager FX. We show that independent detection and quantitation of multiple targets is achievable with little or no correction for fluorescent crosstalk by using fluorescent tags preferentially excited with different laser lines and detected at wavelengths that minimize fluorescence crosstalk. We demonstrate that the use of fluorescent detection methods can provide a tenfold greater quantifiable range but with two- to fourfold less sensitivity than chemiluminescent detection methodologies. Two examples of three-color multiplex detection using FITC-, Cy3- and Cy5-conjugated probes on Western blots are provided to demonstrate applications of this approach.
authors.affiliation: Bio-Rad Laboratories, Hercules, CA, USA. jgingrich@bio-rad.com
authors.forename: J C
authors.initials: JC
authors.lastname: Gingrich
authors.forename: D R
authors.initials: DR
authors.lastname: Davis
authors.forename: Q
authors.initials: Q
authors.lastname: Nguyen
mesh_terms: D000199:Actins / Q000032:analysis; D000818:Animals; D001059:Apoproteins / Q000032:analysis; D017209:Apoptosis; D015153:Blotting, Western; D002232:Carbocyanines; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000032:analysis; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D007834:Lasers; D011506:Proteins / Q000032:analysis*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D014168:Transferrin / Q000032:analysis
chemical_list: D000199:Actins; D001059:Apoproteins; D002232:Carbocyanines; D005456:Fluorescent Dyes; D011506:Proteins; D014168:Transferrin; C028284:apotransferrin; C089187:cyanine dye 3; C085321:cyanine dye 5; D017868:Cyclic AMP-Dependent Protein Kinases; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D016650:Fluorescein-5-isothiocyanate