title: A novel bicistronic sensor vector for detecting caspase-3 activation.
abstract: BACKGROUND
  Apoptosis is involved in pathological cell death of a wide range of human diseases. One of the most important biochemical markers of apoptosis is activation of caspase-3. Ability to detect caspase-3 activation early in the pathological process is important for determining the timing for interfering with apoptosis initiation and prevention of cell damage. Techniques allowing detection of caspase-3 activity at a single cell level show increased sensitivity, compared to biochemical assays; therefore, we developed a novel bicistronic caspase-3 sensor vector enabling detection of caspase-3 activity in individual cells.
  
  
  METHODS
  We employed green fluorescent protein (GFP) as a reporter for caspase-3 activation in our constructs and assessed the functionality of the generated constructs in transiently transfected Neuro2A and HEK293 cells under basal conditions and following application of okadaic acid (OA) or staurosporine (STS) to induce apoptosis. To ensure responsiveness of the new sensor vector to active caspase-3, we co-transfected the sensor with plasmid(s) overexpressing active caspase-3 and quantified GFP fluorescence using a plate reader.
  
  
  RESULTS
  We observed an increase in GFP expression in cells transfected with the new bicistronic caspase-3 sensor in response to both OA and STS. We also showed a significant increase in GFP fluorescence intensity in cells co-expressing the sensor with the plasmid(s) encoding active caspase-3.
  
  
  CONCLUSIONS
  We generated a novel bicistronic caspase-3 sensor vector which relies on a transcription factor/response element system. The obtained sensor combines high sensitivity of the single cell level detection with the possibility of automated quantification.
authors.affiliation: Centre for Brain Research, University of Auckland, 85 Park Rd, Grafton, Auckland 1142, New Zealand; Dept. of Molecular Medicine & Pathology, University of Auckland, 85 Park Rd, Grafton, Auckland 1142, New Zealand. Electronic address: tvag004@aucklanduni.ac.nz.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Vagner
authors.affiliation: Dept. of Molecular Medicine & Pathology, University of Auckland, 85 Park Rd, Grafton, Auckland 1142, New Zealand; Dept. of Pharmacology & Clinical Pharmacology, University of Auckland, 85 Park Rd, Grafton, Auckland 1142, New Zealand.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Mouravlev
authors.affiliation: Dept. of Molecular Medicine & Pathology, University of Auckland, 85 Park Rd, Grafton, Auckland 1142, New Zealand; Dept. of Pharmacology & Clinical Pharmacology, University of Auckland, 85 Park Rd, Grafton, Auckland 1142, New Zealand.
authors.forename: Deborah
authors.initials: D
authors.lastname: Young
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D015374:Biosensing Techniques / Q000379:methods*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005453:Fluorescence; D005786:Gene Expression Regulation / Q000187:drug effects; D017930:Genes, Reporter / Q000502:physiology*; D049452:Green Fluorescent Proteins; D006801:Humans; D019319:Okadaic Acid / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D049452:Green Fluorescent Proteins; D019319:Okadaic Acid; D053148:Caspase 3; D019311:Staurosporine
keywords: Caspase-3 activation; Caspase-3 sensor; Cell-based assay; Single cell detection