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SLFN11promotes stalled fork degradation that underlies the phenotype in Fanconi anemia cells

Authors :
Okamoto, Yusuke
Abe, Masako
Mu, Anfeng
Tempaku, Yasuko
Rogers, Colette B.
Mochizuki, Ayako L.
Katsuki, Yoko
Kanemaki, Masato T.
Takaori-Kondo, Akifumi
Sobeck, Alexandra
Bielinsky, Anja-Katrin
Takata, Minoru
Source :
Blood; January 2021, Vol. 137 Issue: 3 p336-348, 13p
Publication Year :
2021

Abstract

Fanconi anemia (FA) is a hereditary disorder caused by mutations in any 1 of 22 FA genes. The disease is characterized by hypersensitivity to interstrand crosslink (ICL) inducers such as mitomycin C (MMC). In addition to promoting ICL repair, FA proteins such as RAD51, BRCA2, or FANCD2 protect stalled replication forks from nucleolytic degradation during replication stress, which may have a profound impact on FA pathophysiology. Recent studies showed that expression of the putative DNA/RNA helicase SLFN11 in cancer cells correlates with cell death on chemotherapeutic treatment. However, the underlying mechanisms of SLFN11-mediated DNA damage sensitivity remain unclear. Because SLFN11expression is high in hematopoietic stem cells, we hypothesized that SLFN11depletion might ameliorate the phenotypes of FA cells. Here we report that SLFN11knockdown in the FA patient-derived FANCD2-deficient PD20 cell line improved cell survival on treatment with ICL inducers. FANCD2−/−SLFN11−/−HAP1 cells also displayed phenotypic rescue, including reduced levels of MMC-induced chromosome breakage compared with FANCD2−/−cells. Importantly, we found that SLFN11promotes extensive fork degradation in FANCD2−/−cells. The degradation process is mediated by the nucleases MRE11 or DNA2 and depends on the SLFN11 ATPase activity. This observation was accompanied by an increased RAD51 binding at stalled forks, consistent with the role of RAD51 antagonizing nuclease recruitment and subsequent fork degradation. Suppression of SLFN11protects nascent DNA tracts even in wild-type cells. We conclude that SLFN11destabilizes stalled replication forks, and this function may contribute to the attrition of hematopoietic stem cells in FA.

Details

Language :
English
ISSN :
00064971 and 15280020
Volume :
137
Issue :
3
Database :
Supplemental Index
Journal :
Blood
Publication Type :
Periodical
Accession number :
ejs55140408
Full Text :
https://doi.org/10.1182/blood.2019003782