Paired box 3-Forkhead box protein O1 fusion protein (PAX3-FOXO1)

PAX3-FOXO1 is a chimeric transcription factor resulting from a t(2;13)(q35;q14) chromosomal translocation, serving as the primary oncogenic driver in alveolar rhabdomyosarcoma (ARMS) (Source: PubMed PMID: 8096062). The protein fuses the DNA-binding domain of PAX3 to the C-terminal transactivation domain of FOXO1, which is an intrinsically disordered region (IDR) (Source: UniProt P23759). This disordered region is critical for the protein's function, as it mediates protein-protein interfaces with transcriptional co-activators such as p300, CBP, and BRD4 to form oncogenic super-enhancers (Source: Nature Communications, 2022, 13:2422). These interfaces drive the expression of genes that inhibit myogenic differentiation and promote uncontrolled cell proliferation and survival (Source: Cancer Cell, 2014). Because the transactivation domain lacks a fixed three-dimensional structure, it has been historically difficult to target with traditional small-molecule inhibitors (Source: Frontiers in Oncology, 2020). Current therapeutic research focuses on disrupting these specific protein-protein interfaces or using PROTACs to induce the degradation of the fusion protein (Source: Molecular Cancer Therapeutics, 2021). Successfully targeting these disordered regions would provide a highly specific treatment for ARMS patients by dismantling the tumor's core transcriptional program (Source: Cancer Discovery, 2021).

Other names

PAX3-FKHRPAX3/FOXO1t(2;13) fusion proteinPAX3-FOXO1 transactivation domain

Inhibition of the recruitment of transcriptional co-activators (e.g., p300, BRD4) to the intrinsically disordered transactivation domain of the fusion protein, thereby disrupting super-enhancer activity (Source: Nature Communications, 2022).