Ganser Collin, He Peiling, Frazer Corey, Krysan Damian J, Bennett Richard J
Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America.
Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America.
PLoS Genet. 2025 Aug 8;21(8):e1011810. doi: 10.1371/journal.pgen.1011810. eCollection 2025 Aug.
Cell fate decisions in eukaryotes are regulated by interconnected networks of transcription factors (TFs) that drive heritable changes in identity. However, much is unknown about how TFs act together to control cell fate, despite links to cellular dysfunction and disease when TF function is aberrant. Here, we addressed the interplay between TFs that control heritable switching in the diploid fungal pathogen Candida albicans. This species can propagate in two distinct cell states, white and opaque, with epigenetic transitions between states regulated by a core network of eight TFs plus >100 auxiliary TFs. The role of these TFs was dissected using simple and complex haploinsufficiency (CHI) analyses to examine the impact of gene dosage on cell fate. Among single heterozygotes, loss of one allele of WOR1 had the greatest impact on white-opaque switching, consistent with its role as the master opaque regulator, while CHI analysis revealed strong genetic interactions between other core TFs including WOR3 and WOR4. Wor1 function was also highly sensitive to its interaction valency, a measure of the number of inter-molecular interactions it can undergo. Engineered strains with increased Wor1 valency, either via the addition of extra prion-like domains (PrLDs) or by forced dimerization, increased switching frequencies by up to two orders of magnitude. Increasing Wor1 valency increased its propensity to form phase-separated condensates both in vitro and in mammalian cells. Together, these experiments establish that changes to TF gene dosage and TF valency can alter cell fate determination, with these changes linked to the propensity of TFs to undergo condensate formation.
真核生物中的细胞命运决定由转录因子（TFs）相互连接的网络调控，这些转录因子驱动细胞身份的可遗传变化。然而，尽管TF功能异常时与细胞功能障碍和疾病有关，但关于TFs如何共同作用来控制细胞命运仍有许多未知之处。在这里，我们研究了控制二倍体真菌病原体白色念珠菌可遗传转换的TFs之间的相互作用。该物种可以在两种不同的细胞状态（白色和不透明）中繁殖，状态之间的表观遗传转变由八个TFs加上100多个辅助TFs的核心网络调控。使用简单和复杂单倍体不足（CHI）分析来剖析这些TFs的作用，以检查基因剂量对细胞命运的影响。在单杂合子中，WOR1一个等位基因的缺失对白色-不透明转换的影响最大，这与其作为主要不透明调节因子的作用一致，而CHI分析揭示了包括WOR3和WOR4在内的其他核心TFs之间强烈的遗传相互作用。Wor1的功能对其相互作用价态也高度敏感，相互作用价态是衡量其可以经历的分子间相互作用数量的指标。通过添加额外的朊病毒样结构域（PrLDs）或强制二聚化来增加Wor1价态的工程菌株，将转换频率提高了多达两个数量级。增加Wor1价态增加了其在体外和哺乳动物细胞中形成相分离凝聚物的倾向。总之，这些实验表明，TF基因剂量和TF价态的变化可以改变细胞命运的决定，这些变化与TFs形成凝聚物的倾向有关。
