ALL1-fused from chromosome 1q(AF1q),originally considered as an oncogenic factor,has been implicated in the pathogenesis of neurodegeneration.AF1q is highly expressed during neurodevelopment,but its specific functions and molecular mechanisms in neural system remained elusive.Our study here demonstrated that AF1q facilitated neural stem cell proliferation.Since previous studies have shown WNT signaling being involved in neural stem cell proliferation,we examined whether AF1q could induce cell proliferation by activating Wnt signaling pathway.Reporter assay showed AF1Q could activate WNT signaling.And co-immunoprecipitation(CO-IP)analysis demonstrated that AF1q bound specifically to T-cell factor/lymphoid enhancer binding factor-7(TCF/LEF7),which stabilized TCF7 and facilitated TCF7 translocation into nucleus.Additionally,we identified the amino acid 11-20 on AF1Q is sufficient for the binding of TCF7.Furthermore,the phosphorylation of Serine 11 on AF1Q is required for the binding of TCF7.The AF1Q-S11F mutant decreased the activation of WNT signaling and was unable to induce cell proliferation.Our study here identified AF1Q as an important factor in neurodevelopment by interacting with TCF7 and regulating WNT signaling pathway.