title: Monoubiquitination-dependent chromatin loading of FancD2 in silkworms, a species lacking the FA core complex.
abstract: The Fanconi anemia (FA) pathway is required for activation and operation of the DNA interstrand cross-link (ICL) repair pathway, although the precise mechanism of the FA pathway remains largely unknown. A critical step in the FA pathway is the monoubiquitination of FANCD2 catalyzed by a FA core complex. This modification appears to allow FANCD2 to coordinate ICL repair with other DNA repair proteins on chromatin. Silkworm, Bombyx mori, lacks apparent homologues of the FA core complex. However, BmFancD2 and BmFancI, the putative substrates of the complex, and BmFancL, the putative catalytic E3 ubiquitin ligase, are conserved. Here, we report that the silkworm FancD2 is monoubiquitinated depending on FancI and FancL, and stabilized on chromatin, following MMC treatment. A substitution of BmFancD2 at lysine 519 to arginine abolishes the monoubiquitination, but not the interaction between the FancD2 and FancI. In addition, we demonstrated that depletion of BmFancD2, BmFancI or BmFancL had effects on cell proliferation in the presence of MMC. These results suggest that the FA pathway in B. mori works in the same manner as that in vertebrates.
authors.affiliation: Laboratory of Silkworm Science, Kyushu University Graduate School of Bioresource and Bioenvironmental Sciences, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Sugahara
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mon
authors.forename: Jae Man
authors.initials: JM
authors.lastname: Lee
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kusakabe
mesh_terms: D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002843:Chromatin / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000009:adverse effects; D004260:DNA Repair; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000235:genetics / Q000378:metabolism*; D051856:Fanconi Anemia Complementation Group Proteins / Q000235:genetics / Q000378:metabolism; D016685:Mitomycin / Q000009:adverse effects; D008969:Molecular Sequence Data; D054875:Ubiquitination / Q000502:physiology*
chemical_list: D002843:Chromatin; D003432:Cross-Linking Reagents; D052236:Fanconi Anemia Complementation Group D2 Protein; D051856:Fanconi Anemia Complementation Group Proteins; D016685:Mitomycin