In the Literature

Blogs about published peer-reviewed scientific studies.

From Hit to Live-Cell Target Engagement Assay: DNA-Encoded Library Screens and NanoBRET™ Dye

Posted on by Tian Yang

Monitoring and quantifying drug-target binding in a live-cell setting is important to bridging the gap between in vitro assay results and the phenotypic outcome, and therefore represents a crucial step in target validation and drug development (1). The NanoBRET™ Target Engagement (TE) assay is a biophysical technique that enables quantitative assessment of small molecule-target protein binding in live cells. This live-cell target engagement assay uses the bioluminescence resonance energy transfer (BRET) from a NanoLuc® luciferase-tagged target protein and a cell-permeable fluorescent tracer that reversibly binds the target protein of interest. In the presence of unlabeled test compound that engages the target protein, the tracer is displaced, and a loss of BRET signal is observed. Due to the tight distance constraints for BRET, the signal measured is specific to the target fused to NanoLuc® luciferase.

Live-cell target engagement assay using NanoBRET to measure small molecule binding to a target transmembrane protein.

Promega offers over 400 ready-to-use assays for multiple target classes, including kinases, E3 ligases, RAS, and many others. For targets that do not have an existing NanoBRET™ TE assay, Promega offers NanoBRET™ dyes, NanoLuc® cloning vectors, and NanoBRET™ detection reagents to develop novel NanoBRET™ TE assays.

To learn more about the NanoBRET™ TE platform, see the NanoBRET™ Target Engagement Technology Page on our website.

One critical component in the development of novel NanoBRET™ TE assay is the creation of the cell-permeable fluorescent tracers (NanoBRET™ tracers) against the target protein of interest. The tracers are bifunctional, consisting of a NanoBRET™-compatible fluorophore and a target-binding moiety connected by a linker. While the NanoBRET™ 590 dyes have demonstrated consistently robust cell permeability and optimal spectral overlap with NanoLuc® for BRET, a ligand capable of binding to the target protein of interest needs to be identified to generate a NanoBRET™ tracer.

What Are DNA-Encoded Libraries?

DNA-Encoded Libraries, (DELs), have emerged as powerful tools for discovering small molecule ligands to target proteins of interest at an unprecedented scale. . owing to the ability of a DEL  to enable the synthesis of larger libraries of compounds and to target proteins without any prior structural knowledge of the proteins or their ligands (2). Because each member of a DEL contains a DNA barcode and a small molecule separated by a linker, DEL is primed for discovering leads within therapeutic modalities that rely on bifunctional chemistry, such as proteolysis targeting chimeras (PROTACs). Since NanoBRET™ tracers are also bifunctional, ligands identified from DEL selections could serve as ideal candidates for developing novel NanoBRET™ tracers that can enable NanoBRET™ TE assays for new targets.

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Cancer Preventing Vaccines: Unleashing the Potential of Tumor Antigens

Posted on by Sara Christenson

It has been more than 100 years since Dr. William B. Coley, known today as the “Father of Immunotherapy,” made the first recorded attempt to mobilize the immune system as a means of treating cancer (9). Decades later, the discovery of T cells and the vital role they play in the immune system set the groundwork for many new immunotherapy treatments, such as those involving monoclonal antibodies, cytokines, CAR T cells, and checkpoint inhibitors.

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Octopuses Use RNA Editing to Transiently Change Their Proteins When They Get Cold

Posted on by Kelly Grooms
Octopuses in the ocean

In the murky depths of the ocean live some of the smartest and most unusual creatures to inhabit the earth. Octopuses are known for their sucker covered tentacles and chameleon-like abilities to change color, pattern and shape to blend it with their environment. The changes aren’t limited to just their appearance. A new study published in Cell reveals that they can change their brains as well (1). The study found that octopuses recode their brain in response to environmental temperature changes using RNA editing.

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How Does Ozempic Work? The Mechanism of Action of Semaglutide and Other GLP-1 Receptor Agonists

Posted on by Jordan Nutting

In early 2023, a type 2 diabetes medication, semaglutide (brand names Ozempic, Rybelsus), drew huge amounts of attention on social media and in popular culture. The reason? People were getting off-label (that is, not for treating type 2 diabetes) prescriptions of Ozempic to take advantage of one of its common side effects—measurable weight loss.

How does semaglutide and other drugs of its type manage diabetes on a molecular level, and what drives the weight loss effects?

Female leg stepping onto a weigh scale
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Synthetic Biology: Minimal Cell, Maximal Opportunity

Posted on by Ken Doyle

According to the National Human Genome Research Institute, synthetic biology is “a field of science that involves redesigning organisms for useful purposes by engineering them to have new abilities”. Synthetic biology has a broad range of applications, from manufacturing pharmaceuticals and other biologically active chemicals and biofuels, to accelerating the adoption of plant-based burgers (1).

At the heart of the synthetic biology revolution is the rapid technological advancement—and accompanying drop in costs—of DNA oligonucleotide synthesis. Typically, synthetic biology researchers use oligonucleotides as building blocks to assemble genes of interest that are then introduced into, and expressed by, a different organism. For example, to create the plant-based Impossible Burger, the soy leghemoglobin gene (normally found in the root nodules of leguminous plants) was synthesized and expressed in yeast cells (1). This component gives the burger its meaty flavor and appearance of “bleeding” when cooked.

An Impossible Burger served with fries on the side

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Celebrating Distinguished Scientists and Peer-Reviewed Publications in Promega R&D

Posted on by Jordan Villanueva
Promega R&D Scientists were recently honored for publishing papers and patents between 2019-2023

“We are a company that is built upon innovation, and R&D is one of the main drivers of that,” says Frank Fan, Director of Biology at Promega.

Promega Research and Development is focused on developing reliable tools that address the biggest problems facing life scientists. However, our R&D scientists do much more than just develop products. Promega scientists regularly pursue basic research to curate new skills and knowledge and collaborate extensively with researchers across academia and industry. This work fuels major advancements in areas like targeted genome editing, drug discovery, and genetic identity.

In June 2023, our Research and Development department gathered to recognize Promega scientists who have published peer-reviewed papers or patents. This was the first time the department had held this event since 2019, and in that time 71 scientists have published research in journals like Nature and Cell. 16 of those scientists published 10 or more times, and several were also invited to contribute review articles and book chapters.

In addition, Promega also recognized seven researchers with the title “Distinguished Scientist.” This award was intended to recognize scientists who are at the top of their game in both advancing and communicating science. Their work includes protein engineering, chemical biology, neuroscience and much more.

The Distinguished Scientists were selected for having an i10 index above 25 since 2018. This indicates that the scientist has more than 25 publications that have been cited 10+ times in the past five years, as measured by Google Scholar. As VP of R&D Poncho Meisenheimer said, “This award is truly from the scientific community. This is a recognition that your scientific peers see your work as valuable.”

Here is the list of Promega researchers recognized as Distinguished Scientists and some of their recent high-impact papers.

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Phage Therapy: Meeting the Challenge of Drug-Resistant Bacterial Infections

Posted on by Ken Doyle

Global pandemics, such as COVID-19, have taught us to abhor viruses. The emergence of new, highly infectious viruses is—rightfully so—a cause for concern. However, despite the average human body harboring 380 trillion viruses, most of them simply coexist with us and are harmless. When it comes to an ancient lineage of viruses within the realm Duplodnaviria, researchers are even using them as weapons in the battle against infectious diseases.

In 1915, Frederick William Twort, an English bacteriologist at the University of London, reported the discovery of an unusual “ultramicroscopic virus” (1). Twort was culturing vaccinia virus as part of an experiment to determine if he could prepare smallpox vaccines in vitro. These vaccines, made in calves, were typically contaminated with Staphylococcus bacteria. When Twort plated the vaccines, he found small, clear areas on the agar plates where the bacteria would not grow, and these clear areas were the source of his ultramicroscopic virus. Two years later, a French-Canadian microbiologist, Félix d’Hérelle, independently discovered a similar phenomenon when culturing Shigella bacteria from fecal samples of patients with bacillary dysentery. He called the new virus “un bactériophage obligatoire” (2). Shortly after his discovery, he found that bacteriophages (phages) could be used as powerful agents to treat a variety of bacterial infections, and the field of phage therapy was born (3).

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Genome-Wide CRISPR Screening: Putting Death on Hold

Posted on by Ken Doyle

We share this planet with approximately 8.7 million species of plants and animals. Within such a diverse environment, it’s only natural that many complex relationships have developed among different species. Some relationships are mutually beneficial, some are parasitic—and some are lethal.

Genome wide - crisper screening to help with toxic compounds to humans

Natural toxins and venoms are biologically active compounds produced by normal metabolic processes in an organism but are harmful to other organisms. Typically, toxins are encountered passively or ingested by the affected organisms, and have a specific mode of action and binding site within a cell. In contrast, venoms are introduced directly into the victim through a specialized delivery mechanism, and they may consist of a mixture of compounds that affect a range of cell types and tissues (1). Both types of poisons are produced for predation, defense, or to offer a competitive advantage (1).

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Cell Tracking Using HaloTag: Why are Scientists Chasing Cells?

Posted on by Shannon Sindermann

Cells, commonly considered the smallest unit of life, provide structure and function for all living things (3).

Eye of a fruit fly, Drosophila melanogaster, scanning electron microscopy. Scientists used HaloTag for cell tracking during eye development.
Eye of a fruit fly, Drosophila melanogaster, scanning electron microscopy

Because cells contain the fundamental molecules of life, in some situations such as yeast, a single cell can be considered the complete organism. In other situations, for more complex multicellular organisms, a multitude of cells can mature and acquire different, specialized functions (3).

Cells developing specificity are undergoing differentiation, a process where a cell’s genes are either turned “on” or “off” resultant in a more specific cell type. As these differentiated cells start to exhibit their identity, they organize themselves into the tissues, organs, and organ systems integral to the functioning of a multicellular, developing organism. This process in which order and form is created within a developing organism is referred to as morphogenesis (5).

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PARP and DDR Pathways: Targeting the DNA Damage Response for Cancer Treatment

Posted on by Ken Doyle

Our cells, and the DNA they contain, are under constant attack from external factors such as ionizing radiation, ultraviolet light and environmental toxins. Internal cellular processes can also generate metabolites, such as reactive oxygen species, that damage DNA. In most cases, DNA damage results in permanent changes to DNA molecules, including DNA mismatches, single-strand breaks (SSBs), double-strand breaks (DSBs), crosslinking, or chemical alteration of bases or sugars. If left unchecked, DNA damage can cause genome instability, mutations and aberrant transcription, and oncogenic transformation.

PARP DDR pathway for drug discovery

Fortunately, our cells have also evolved multiple pathways to repair damaged DNA, collectively known as the DNA damage response (DDR). The type of repair mechanism depends on the nature of the damage, and whether the damage occurs in mitochondrial or nuclear DNA. These mechanisms have been reviewed extensively (1,2). Recently, considerable attention has focused on pathways for repairing SSBs and DSBs, mediated by the ADP-ribosylating enzyme known as poly (ADP-ribose) polymerase 1, or PARP-1.

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