Regulation of Fanconi anemia protein FANCD2 monoubiquitination by miR-302

• miR-302 binds to the 3′UTR promoter of the FANCD2 gene to regulate gene expression.
• miR-302 cluster down-regulates FANCD2 protein expression.
• miR-302 cluster reduces FANCD2 monoubiquitination and nuclear foci formation.
• miR-302 exhibits the characteristic defects in DNA repair in cells.

Fanconi anemia (FA) is a recessively inherited multigene disease characterized by congenital defects, progressive bone marrow failure, and heightened cancer susceptibility. Monoubiquitination of the FA pathway member FANCD2 contributes to the repair of replication stalling DNA lesions. However, cellular regulation of FANCD2 monoubiquitination remains poorly understood. In the present study, we identified the miR-302 cluster as a potential regulator of FANCD2 by bioinformatics analysis. MicroRNAs (miRNAs) are the major posttranscriptional regulators of a wide variety of biological processes, and have been implicated in a number of diseases. Expression of the exogenous miR-302 cluster (without miR-367) reduced FANCD2 monoubiquitination and nuclear foci formation. Furthermore, miR-302 cells showed extensive chromosomal breakage upon MMC treatment when compared to mock control cells. Taken together, our results suggest that overexpression of miR-302 plays a critical role in the regulation of FANCD2 monoubiquitination, resulting in characteristic defects in DNA repair within cells.