The Zinc Finger Protein Zfp2 Regulates Cell–Cell Fusion and Virulence in Cryptococcus neoformans

<i>Cryptococcus neoformans</i> is a fungal pathogen commonly found in the environment. It mainly infects immunocompromised individuals, causing cryptococcal pneumonia and meningitis, which result in hundreds of thousands of deaths each year. Zinc finger proteins, with zinc finger domains, are common across organisms and serve many biological functions. In this study, we identified and characterized Zfp2, a C₃HC₄-type zinc finger protein, which regulates cell fusion and virulence in <i>C. neoformans</i>. Stress tests showed that the <i>zfp2</i>Δ mutant is hypersensitive to SDS, Congo red, NaCl, KCl, caspofungin, and fluconazole, suggesting that Zfp2 helps maintain cell membrane or wall integrity in <i>C. neoformans</i>. Notably, deleting <i>ZFP2</i> reduced capsule size, while its overexpression led to capsule enlargement. The <i>zfp2</i>Δ mutants also demonstrated a growth defect at 37 °C. Cell fusion assay showed that Zfp2 is essential for cell fusion during sexual reproduction, as <i>zfp2</i>Δ mutants could not fuse during bilateral mating. To understand why the <i>zfp2</i>Δ mutants failed to fuse, we examined key genes in the pheromone response pathway and found that Zfp2 may affect cell fusion by regulating this pathway. Finally, a virulence test in mice showed that both <i>ZFP2</i> deletion and overexpression significantly reduced <i>C. neoformans'</i> virulence. Overall, our research suggests that the zinc finger protein Zfp2 is vital for cell fusion and virulence in <i>C. neoformans</i>.