title: A highly selective, label-free, homogenous luminescent switch-on probe for the detection of nanomolar transcription factor NF-kappaB.
abstract: Transcription factors are involved in a number of important cellular processes. The transcription factor NF-κB has been linked with a number of cancers, autoimmune and inflammatory diseases. As a result, monitoring transcription factors potentially represents a means for the early detection and prevention of diseases. Most methods for transcription factor detection tend to be tedious and laborious and involve complicated sample preparation, and are not practical for routine detection. We describe herein the first label-free luminescence switch-on detection method for transcription factor activity using Exonuclease III and a luminescent ruthenium complex, [Ru(phen)(2)(dppz)](2+). As a proof of concept for this novel assay, we have designed a double-stranded DNA sequence bearing two NF-κB binding sites. The results show that the luminescence response was proportional to the concentration of the NF-κB subunit p50 present in the sample within a wide concentration range, with a nanomolar detection limit. In the presence of a known NF-κB inhibitor, oridonin, a reduction in the luminescence response of the ruthenium complex was observed. The reduced luminescence response of the ruthenium complex in the presence of small molecule inhibitors allows the assay to be applied to the high-throughput screening of chemical libraries to identify new antagonists of transcription factor DNA binding activity. This will allow the rapid and low cost identification and development of novel scaffolds for the treatment of diseases caused by the deregulation of transcription factor activity.
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China. edmondma@hkbu.edu.hk
authors.forename: Dik-Lung
authors.initials: DL
authors.lastname: Ma
authors.forename: Ting
authors.initials: T
authors.lastname: Xu
authors.forename: Daniel S-H
authors.initials: DS
authors.lastname: Chan
authors.forename: Bradley Y-W
authors.initials: BY
authors.lastname: Man
authors.forename: Wang-Fun
authors.initials: WF
authors.lastname: Fong
authors.forename: Chung-Hang
authors.initials: CH
authors.lastname: Leung
mesh_terms: D001665:Binding Sites; D004247:DNA / Q000737:chemistry; D005090:Exodeoxyribonucleases; D057166:High-Throughput Screening Assays; D049408:Luminescent Agents / Q000737:chemistry*; D008163:Luminescent Measurements; D015335:Molecular Probes / Q000737:chemistry; D052002:NF-kappa B p50 Subunit / Q000032:analysis*; D009942:Organometallic Compounds / Q000737:chemistry*
chemical_list: D049408:Luminescent Agents; D015335:Molecular Probes; D052002:NF-kappa B p50 Subunit; D009942:Organometallic Compounds; C466600:Ru(phen)(2)dipyrido(3,2-a-2',3'-c)phenazine; D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III