In recent years, zebrafish, freshwater vertebrates with remarkable genetic similarity to humans, have emerged as vital contributors in scientific research, thanks to their short life span and genetic adaptability. These small fish are now the second-most widely used animal in research labs worldwide. A recent interview with Dr. Kenneth Poss, James B. Duke Professor of Cell Biology at Duke University, offered insight into the importance of technology in advancing zebrafish research.  

Above: Zebrafish. Image courtesy of Britannica.

When discussing his research, Dr. Poss explained that effective science hinges on technology's ability to deliver accurate, observable results. A persistent challenge in regeneration research is understanding the role of transient proteins, fleeting and elusive proteins critical to cellular regeneration. After years of dedicated research on the science of regeneration, Dr. Poss and his team have pioneered a new approach that could reshape and expand the field.

A Novel Technology

In collaboration with his colleagues, Dr. Poss recently published groundbreaking research showcasing a technology capable of identifying these hard-to-detect proteins involved in cardiomyocyte regeneration. The group was among the first to use the technique, known as BioID proximity labeling, specifically in zebrafish heart regeneration.  

BioID proximity labeling works by marking proteins in close proximity to a protein of interest, indicating possible related roles in signaling pathways or activities. The Poss Lab used cmlc2, a cardiac-specific promoter, to activate the expression of the transgene BirA2. BirA2 then tags nearby proteins with biotin, a nutrient that makes them visible for analysis. This advancement allowed for new avenues of tracking protein interactions and a better understanding of heart regeneration. 

Above: A schematic of BioID proximity labeling. Image courtesy of Sears et al., 2019.

The lab’s research aimed to refine the efficient BioID method and identify specific proteins involved in heart tissue regeneration. To this end, they engineered the genes of zebrafish to give rise to heart defects that would be regenerated during the study, allowing them to identify proteins that were active during tissue regeneration. Interestingly, Dr. Poss explained that these unique transgenic fish models were readily available thanks to a graduate student project in the lab over eight years ago.

BioID’s ability to successfully identify nearby proteins in zebrafish heart cells marked a celebratory accomplishment for the Poss Lab, symbolizing a new door to the future of regenerative science. Although more work remained to verify which proteins were involved in the tissue regeneration, the team maintained confidence in knowing their technology worked. The team then dove further into the unknown to identify potential protein candidates. 

Pinpointing Key Proteins

Even with these resources, the team faced the challenge of selecting the right proteins to hone in on. “Much like investing,” multiple factors such as risk, importance, and novelty all came into play, explained Dr. Poss. Using this mindset, the team narrowed the options and chose a small group of proteins to study closer.  

Using background knowledge and the new BioID technology, they found that Erb2 interacted with RhoA in the cells. The Poss Lab drew parallels with breast cancer, in which Erb2 is known to activate RhoA, a G-protein essential to cell functions, during the process of metastasis, or cell growth. This knowledge led to further investigation of Erb2’s interactions, specifically with RhoA within cardiac cells. To test the importance of RhoA in heart regeneration, they administered Rhosin, an inhibitor of RhoA, to zebrafish with damaged hearts. As a result, the duplication of cardiomyocytes, the brick-like heart muscle cells, slowed significantly, pinpointing RhoA's critical role in the regeneration process. 

Future Implications

While Poss’s paper offers an early look at the proteins essential for zebrafish heart regeneration, its broader impact lies in the technological success it demonstrates. The BioID technique could extend beyond zebrafish, potentially transforming and revolutionizing the future of genetic and regenerative science. 

In addition to the obvious advancements in genetic science, this achievement showcases the dedication driving the Poss Lab. Despite numerous obstacles—from a global pandemic to countless challenging decisions made along the way—their success and commitment are a testament to the lab’s foundational beliefs in collaboration and support. Dr. Poss conveyed a unique dual purpose to his research: advancing technology and deepening the understanding of regeneration. Beyond the technical and scientific goals, what stood out most in speaking with Dr. Poss was the lab’s prioritization of doing good, innovative science. In his words, Dr. Poss gains “satisfaction from doing something new for the field or the system.” Indeed, Dr. Poss’s team is driven by the genuine desire to benefit science through groundbreaking work and discoveries.    

Looking ahead, Poss shared an exciting glimpse into the future of his lab and regeneration science. The potential application of proximity labeling is immense—from identifying proteins and lipids to tracking other elements of cells. This research advances our understanding of regenerative mechanisms and promises new tools that could redefine approaches to this field of science. As Poss’s lab continues to refine these methods and dive deeper into the proteins involved, the team’s contributions will expand beyond zebrafish research. Science will indeed “just keep swimming” forward, pushing the limits of what can be achieved in biology and medicine.