TY - JOUR
T1 - Lagging strand gap suppression connects BRCA-mediated fork protection to nucleosome assembly through PCNA-dependent CAF-1 recycling
AU - Thakar, Tanay
AU - Dhoonmoon, Ashna
AU - Straka, Joshua
AU - Schleicher, Emily M.
AU - Nicolae, Claudia M.
AU - Moldovan, George Lucian
N1 - Funding Information:
We would like to thank Drs. Alan D’Andrea, Binghui Shen, and Boris Pfander for materials and advice; and the Penn State College of Medicine Flow Cytometry and Imaging cores. This work was supported by the National Institutes of Health (R01ES026184 and R01GM134681 to G.L.M.; R01CA244417 to C.M.N.).
Funding Information:
We would like to thank Drs. Alan D’Andrea, Binghui Shen, and Boris Pfander for materials and advice; and the Penn State College of Medicine Flow Cytometry and Imaging cores. This work was supported by the National Institutes of Health (R01ES026184 and R01GM134681 to G.L.M.; R01CA244417 to C.M.N.).
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/12
Y1 - 2022/12
N2 - The inability to protect stalled replication forks from nucleolytic degradation drives genome instability and underlies chemosensitivity in BRCA-deficient tumors. An emerging hallmark of BRCA-deficiency is the inability to suppress replication-associated single-stranded DNA (ssDNA) gaps. Here, we report that lagging strand ssDNA gaps interfere with the ASF1-CAF-1 nucleosome assembly pathway, and drive fork degradation in BRCA-deficient cells. We show that CAF-1 function at replication forks is lost in BRCA-deficient cells, due to defects in its recycling during replication stress. This CAF-1 recycling defect is caused by lagging strand gaps which preclude PCNA unloading, causing sequestration of PCNA-CAF-1 complexes on chromatin. Importantly, correcting PCNA unloading defects in BRCA-deficient cells restores CAF-1-dependent fork stability. We further show that the activation of a HIRA-dependent compensatory histone deposition pathway restores fork stability to BRCA-deficient cells. We thus define lagging strand gap suppression and nucleosome assembly as critical enablers of BRCA-mediated fork stability.
AB - The inability to protect stalled replication forks from nucleolytic degradation drives genome instability and underlies chemosensitivity in BRCA-deficient tumors. An emerging hallmark of BRCA-deficiency is the inability to suppress replication-associated single-stranded DNA (ssDNA) gaps. Here, we report that lagging strand ssDNA gaps interfere with the ASF1-CAF-1 nucleosome assembly pathway, and drive fork degradation in BRCA-deficient cells. We show that CAF-1 function at replication forks is lost in BRCA-deficient cells, due to defects in its recycling during replication stress. This CAF-1 recycling defect is caused by lagging strand gaps which preclude PCNA unloading, causing sequestration of PCNA-CAF-1 complexes on chromatin. Importantly, correcting PCNA unloading defects in BRCA-deficient cells restores CAF-1-dependent fork stability. We further show that the activation of a HIRA-dependent compensatory histone deposition pathway restores fork stability to BRCA-deficient cells. We thus define lagging strand gap suppression and nucleosome assembly as critical enablers of BRCA-mediated fork stability.
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U2 - 10.1038/s41467-022-33028-y
DO - 10.1038/s41467-022-33028-y
M3 - Article
C2 - 36085347
AN - SCOPUS:85138128308
SN - 2041-1723
VL - 13
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 5323
ER -