FANCD2 Binding to H4K20me2 via a Methyl-Binding Domain Is Essential for Efficient DNA Cross-Link Repair

Abstract

Fanconi anemia (FA) is an inherited disease characterized by bone marrow failure and increased cancer risk. FA is caused by mutation of any 1 of 22 genes, and the FA proteins function cooperatively to repair DNA interstrand cross-links (ICLs). A central step in the activation of the FA pathway is the monoubiquitination of the FANCD2 and FANCI proteins, which occurs within chromatin. How FANCD2 and FANCI are anchored to chromatin remains unknown. In this study, we identify and characterize a FANCD2 histone-binding domain (HBD) and embedded methyl-lysine-binding domain (MBD) and demonstrate binding specificity for H4K20me2. Disruption of the HBD/MBD compromises FANCD2 chromatin binding and nuclear focus formation and its ability to promote error-free DNA interstrand cross-link repair, leading to increased error-prone repair and genome instability. Our study functionally describes the first FA protein chromatin reader domain and establishes an important link between this human genetic disease and chromatin plasticity.

GRWD1-WDR5-MLL2 Epigenetic Complex Mediates H3K4me3 Mark and Is Essential for Kaposi’s Sarcoma-Associated Herpesvirus-Induced Cellular Transformation

“…We have previously performed a CRISPR-Cas9 screening with MM and KMM cells and identified genes that promote or suppress cell proliferation and survival ( 21 ). By combining the EpiFactors database ( 4 ) and the epigenetic factors newly described between 2015 and 2021 ( 26 , 29 – 33 ), we identified 701 epigenetics-related genes that had differential effects on cell proliferation and survival between MM and KMM cells following their knockout ( Fig. 1C ).…”

Focal Point of Fanconi Anemia Signaling

“…DNA binding of FANCI–FANCD2 is required for monoubiquitination and activation of the FA signaling. Despite the numerous important findings, such as that FANCD2 binding to H4K20me2 is essential for repairing DNA crosslinks [ 62 ], how this activates DNA repair remains largely unclear. In addition, our studies on FANCD2 variants demonstrate an in-depth understanding of how FA signaling is timely in guarding genome stability, which may bring promising biomarkers that are useful for cancer prevention and/or earlier cancer diagnosis.…”

Fanconi anemia pathway as a prospective target for cancer intervention

“…FANCD2 binds to H4K20me2 via its histone-binding domain (HBD) and an embedded methyl-lysine-binding domain (MBD). A HBD/MBD mutant of FANCD2 that can be efficiently monoubiquitinated demonstrates impaired chromatin binding and foci formation, suggesting that monoubiquitination precedes ICL recruitment of FANCD2 [46]. However, arguing against this time course are studies that showed the ID2 complex is recruited to ICLs before the occurrence of FANCD2 monoubiquitination [41].…”