Bioluminescence

Striking Fear into the Heart of Cardiovascular Disease Using Zebrafish and NanoLuc® Luciferase

Posted on by Natalie Larsen
Representative images of ApoB-LP localization in zebrafish across developmental, genetic, pharmacological and dietary manipulations.
Credit: Figure 5.D of The LipoGlo reporter system for sensitive and specific monitoring of atherogenic lipoproteins by James Thierer, Stephen C. Ekker and Steven A. Farber.
Article licensed under Creative Commons Attribution 4.0 International License.

Cardiovascular diseases, or CVDs, are collectively the most notorious gang of cold-blooded killers threatening human lives today. These unforgiving villains, including the likes of coronary heart disease, cerebrovascular disease and pulmonary embolisms, are jointly responsible for more deaths per year than any other source, securing their seat as the number one cause of human mortality on a global scale.

One of the trademarks of most CVDs is the thickening and stiffening of the arteries, a condition known as atherosclerosis. Atherosclerosis is characterized by the accumulation of cholesterol, fats and other substances, which together form plaques in and on the artery walls. These plaques clog or narrow your arteries until they completely block the flow of blood, and can no longer supply sufficient blood to your tissues and organs. Or the plaques can burst, setting off a disastrous chain reaction that begins with a blood clot, and often ends with a heart attack or stroke.

Given the global prevalence and magnitude of this problem, there is a significant and urgent demand for better ways to treat CVDs. In a recent study published in Nature Communications, researchers at the Carnegie Institution for Science, Johns Hopkins University and Mayo Clinic are taking the fight to CVDs through the study of low-density lipoproteins (LDLs), the particles responsible for shuttling bad cholesterol throughout the bloodstream.

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I Have My Luciferase Vector, Now What?

Posted on by Joliene Lindholm
Choosing and Optimizing Transfection Methods

Here in Technical Services we often talk with researchers at the beginning of their project about how to carefully design and get started with their experiments. It is exciting when you have selected the Luciferase Reporter Vector(s) that will best suit your needs; you are going to make luminescent cells! But, how do you pick the best way to get the vector into your cells to express the reporter? What transfection reagent/method will work best for your cell type and experiment? Do you want to do transient (short-term) transfections, or are you going to establish a stable cell line?

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Why You Don’t Need to Select a Wavelength for a Luciferase Assay

Posted on by Ben Schmidt
Promega kit depicted; test involves wavelength for a luciferase assay.

It’s a question I’m asked probably once a week. “What wavelength do I select on my luminometer when performing a luciferase assay?” The question is a good and not altogether unexpected one, especially for those new to bioluminescent assays. The answer is that in most cases, you don’t and in fact shouldn’t select a wavelength (the exception to this rule is if you’re measuring light emitted in two simultaneous luciferase reactions). To understand why requires a bit of an explanation of absorbance, fluorescence, and luminescence assays, and the differences among them.

Absorbance, fluorescence, and luminescence assays are all means to quantify something of interest, be that a genetic reporter, cell viability, cytotoxicity, apoptosis, or other markers. In principle, they are all similar. For example, a genetic reporter assay is an indicator of gene expression. The promoter of a gene of interest can be cloned upstream of a reporter such as β-galactosidase, GFP, or firefly luciferase. The amount of each of these reporters that is transcribed into mRNA and translated into protein by the cell is indicative of the endogenous expression of the gene of interest.

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Dual-Luciferase or Dual-Glo Luciferase Assay System? Which one should I choose for my reporter assays?

Posted on by Terri Sundquist
Confused woman

I’ve got a set of experiments planned that, if all goes well, will provide me with the answer I have been seeking for months. Plus, my supervisor is eagerly awaiting the results because she needs the data for a grant application, so I don’t want to mess it up. However, I am faced with a choice for my firefly and Renilla luciferase reporter assays: Do I use the Dual-Luciferase® Reporter Assay System or Dual-Glo® Luciferase Assay System? What’s the difference? How do I decide which to use? I’m so confused! Help!

Sound familiar? Not to worry! The choice is not difficult once you know how these assays work and how they differ.

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From Drug Screening to Agriculture to Cardiac Development, A Dual-Luciferase Reporter Brings You the Story

Posted on by Promega

Today’s blog was written by guest blogger Katarzyna Dubiel, marketing intern in Cellular Analysis and Proteomics. Last updated 02/12/2021

Reporter gene assays have been critical for the study of a wide-range of biological questions, from regulation of gene expression to cellular signaling. While reporter gene assays constitute a large group of technologies, here we highlight the diversity of new discoveries enabled by highly quantitative and easily measured bioluminescent luciferase-based reporter assays. Below are our top picks of exciting research discoveries involving the Dual-Luciferase Reporter Assay format using firefly and Renilla luciferases.

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6 + 1 Ways Dual-Reporter Assays Can Save Your Data

Posted on by Kyle Hooper

Updated 02/12/2021

Dual-Reporter-Assay

Transient transfection is often used to perform reporter assays. We have advocated using a dual-reporter system for decades to normalize the data obtained and gain a clearer understanding of your results.  The experimental reporter should vary with treatment and the control reporter should vary little with treatment. The control reporter thus serves as a marker to help you understand the relative activity of your experimental reporter. The bioluminescent Dual-Luciferase® method allows for sequential detection of the second reporter in a single sample providing a simple two-step normalization method. Here are seven ways in which dual-reporter assays help you avoid misinterpreting results.

Simply comparing the ratio of the experimental to the control reporter can resolve differences in:

  1. Number of Cells/Well: When manually pipeting cells into a 96-well plate, there is always a chance of having variable numbers of cells in each well. This variation is cell number will affect the experimental and control reporters equally, so the ratio of experimental:control reporter activity will eliminate false interpretation of the experimental data–whether it affects an entire row or column on the plate or individual wells.
  2. Transfection Efficiency: The variations in transfection efficiency will equally affect both the experimental and control reporters so the ratio of activity in dual-reporter assays will normalize the data.
  3. Cell Viability: Often, reporter assays look at the dose response curve of a particular compound with regard to gene expression. Ideally, if a compound causes a change in the experimental reporter the control reporter will demonstrate little effect. However, if the compound is toxic, both the experimental and control will be altered and the ratio will tell you whether the compound truly affects reporter activity or just kills the cells.
  4. Lysis Efficiency: When lysing a plate of cells, you could encounter situations where rows or columns lyse differently, especially if you are using manual disruption or get interrupted mid-plate. The difference is lysis will affect the experimental and control equally so the ratio will remove the variation.
  5. Temperature: Ideally, a plate should be equilibrated to ambient room temperature before proceeding to the reporter assay. Plates can cool at different rates or researchers anxious to record data may read the data early. Temperature variations will affect both reporters so the ratio will limit the affect on the data.
  6. Measurement Time: Repetition of data is a hallmark of good science. You are often called upon to repeat experiments sometimes days or weeks apart. Let’s say you repeat your experiment one week after the initial experiment. The first time you measured the response, you waited 10 minutes after reagent addition to read, this week you waited 30 minutes. This will affect both reporters equally and therefore the ratio will allow you to more easily compare the data from this week and last week.

Bonus Benefit from Dual-Luciferase®, Dual-Glo® and the NanoGlo® Dual Luciferase Reporter Systems: No Lysate Splitting: Promega dual-reporter assays are designed for same-well multiplexing so there is no chance of variations creeping into your data due to unequal splitting of the cellular lysate to measure two separate reporter activities.

Since the introduction of the first bioluminescent dual-luciferase assay in 1995, this approach has been used in countless studies to advance our scientific understanding of cellular gene regulation. To learn more about the last 30 years of bioluminescent innovations and research discoveries please visit our 30th anniversary web page.

Further Reading:
Normalizing Genetic Reporter Assays Approaches and Considerations for Increasing Consistency and Statistical Significance

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