Characterization of Coelenterazine Analogs for Measurements of Renilla Luciferase Activity in Live Cells and Living Animals

A Comprehensive Exploration of Bioluminescence Systems, Mechanisms, and Advanced Assays for Versatile Applications

Bioluminescence has been a fascinating natural phenomenon of light emission from living creatures. It happens when the enzyme luciferase facilitates the oxidation of luciferin, resulting in the creation of an excited-state species that emits light. Although there are many bioluminescent systems, few have been identified. D-luciferin-dependent systems, coelenterazine-dependent systems, Cypridina luciferin-based systems, tetrapyrrole-based luciferins, bacterial bioluminescent systems, and fungal bioluminescent systems are natural bioluminescent systems. Since different bioluminescence systems, such as various combinations of luciferin-luciferase pair reactions, have different light emission wavelengths, they benefit industrial applications such as drug discovery, protein-protein interactions, in vivo imaging in small animals, and controlling neurons. Due to the expression of luciferase and easy permeation of luciferin into most cells and tissues, bioluminescence assays are applied nowadays with modern technologies in most cell and tissue types. It is a versatile technique in a variety of biomedical research. Furthermore, there are some investigated blue-sky research projects, such as bioluminescent plants and lamps. This review article is mainly based on the theory of diverse bioluminescence systems and their past, present, and future applications.

Ultrasensitive quantification of HIV-1 cell-to-cell transmission in primary human CD4+ T cells measures viral sensitivity to broadly neutralizing antibodies

IMPORTANCE

HIV-1 can efficiently transmit from one cell to another but accurate quantification of this mode of transmission is still challenging. Here, we developed an ultrasensitive assay to measure HIV-1 transmission between cells and to evaluate HIV-1 escape from broadly neutralizing antibodies in primary human T cells. This assay will contribute to understanding the fundamental mechanisms of HIV-1 cell-to-cell transmission, allow evaluation of pre-existing or acquired HIV-1 resistance in clinical trials, and can be adapted to study the biology of other retroviruses.

A Bioluminescence Resonance Energy Transfer-Based Reporter System: Characterization and Applications

Genome editing strategies and DNA repair research need powerful analytical tools. We generated a bioluminescence resonance energy transfer (BRET)-based reporter for the quantification of indel frequencies induced by DNA repair. The BRET reporter, expressed as a single molecule, consists of a mutated Renilla reniformis luciferase domain and a GFP2 domain separated by a shuttle-cloning box for the integration of any given endonuclease target sequence. The luciferase activity acts both as energy donor and as the internal standard, while the loss of GFP2 fluorescence acts as a reporter for the out-of-frame sequence alterations that result from the DNA repair via the non-homologous end joining/microhomology-mediated end joining DNA repair pathways of the endonuclease-mediated DNA double-strand break. This results in a decrease of the fluorescence/luminescence ratio. Employing this reporter in different experimental scenarios, using different cell lines and diseases targeted, we quantified the influence of both protein knockdown of DNA repair pathways as well as guide RNA mismatches on CRISPR-mediated nuclease activity and subsequent repair based on mutagenic repair on the reporter. In conclusion, we demonstrated this BRET-based reporter to be a robust and sensitive analytical tool for assessment of variety of different genome editing-based approaches.