BIOMEDICAL - 'Highlighter' for Gene Regulation

Transcription factors (TFs) are like molecular “conductors” that coordinate gene expression and play vital roles in everything from development and disease to how cells respond to their environment. Yet capturing their activity in real time and with high precision has been a major challenge. The ability to observe TFs in living cells—accurately, in real time, and at scale—can accelerate drug discovery, revealing compounds that fine-tune gene expression for therapies in cancer, regenerative medicine, and beyond, while offering deeper insight into fundamental cell biology.

Dr David C. Bersten is a Researcher at the University of Adelaide, specialising in how TFs sense physiological and environmental signals to control gene expression, particularly in the brain. Combining molecular, cellular, and animal models with genomic and proteomic tools, he investigates targets such as Hypoxia Inducible Factor (HIF), NPAS proteins, and hypothalamic regulators of appetite and energy balance. This year, Dr Bersten and colleagues unveiled dFLASH (dual FLuorescent transcription factor Activity Sensor for Histone-integrated live-cell reporting), a modular, genome-integrated sensor that enables scientists to watch TFs in action—live, in real time, and with striking clarity. The system produces two distinct nuclear fluorescent signals: a TF-dependent “reporter” and an internal “control,” allowing highly accurate, normalized measurements of TF activity.

Developing dFLASH required a fusion of cutting-edge methods. CRISPR-Cas9 genome editing (including CRISPRoff) and whole-genome CRISPR knockout screening were used to test and validate TF regulation. Lentiviral-mediated genomic integration ensured robust, enhancer-driven reporting across stable cell lines. High-content imaging and flow cytometry allowed dynamic monitoring of TF activity and precise single-cell analysis, while custom plasmid construction provided the modular framework for adapting the system to different transcription factors.

The SAGC has contributed to this important work by sequencing the CRISPR libraries.

Application in Drug Screening and Beyond

Dr. Bersten and his colleagues were able to demonstrate the utility of dFLASH in drug discovery, by screening a 1,600-compound natural product library which led to the identification of new HIF pathway modulators, including both inhibitors and stabilisers of HIF-1α—findings with clear potential in cancer and other hypoxia-related diseases.