title: Ssb1 and Ssb2 cooperate to regulate mouse hematopoietic stem and progenitor cells by resolving replicative stress.
abstract: Hematopoietic stem and progenitor cells (HSPCs) are vulnerable to endogenous damage and defects in DNA repair can limit their function. The 2 single-stranded DNA (ssDNA) binding proteins SSB1 and SSB2 are crucial regulators of the DNA damage response; however, their overlapping roles during normal physiology are incompletely understood. We generated mice in which bothSsb1andSsb2were constitutively or conditionally deleted. ConstitutiveSsb1/Ssb2double knockout (DKO) caused early embryonic lethality, whereas conditionalSsb1/Ssb2double knockout (cDKO) in adult mice resulted in acute lethality due to bone marrow failure and intestinal atrophy featuring stem and progenitor cell depletion, a phenotype unexpected from the previously reported single knockout models ofSsb1orSsb2Mechanistically, cDKO HSPCs showed altered replication fork dynamics, massive accumulation of DNA damage, genome-wide double-strand breaks enriched at Ssb-binding regions and CpG islands, together with the accumulation ofR-loops and cytosolic ssDNA. Transcriptional profiling of cDKO HSPCs revealed the activation of p53 and interferon (IFN) pathways, which enforced cell cycling in quiescent HSPCs, resulting in their apoptotic death. The rapid cell death phenotype was reproducible in in vitro cultured cDKO-hematopoietic stem cells, which were significantly rescued by nucleotide supplementation or after depletion of p53. Collectively, Ssb1 and Ssb2 control crucial aspects of HSPC function, including proliferation and survival in vivo by resolving replicative stress to maintain genomic stability.
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.|School of Medicine, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Therese
authors.initials: T
authors.lastname: Vu
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Didier
authors.initials: D
authors.lastname: Boucher
authors.affiliation: Laboratory of Bioinformatics and Systems Biology, Center of New Technologies, University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Biernacka
authors.affiliation: Department of Biochemistry & Molecular Biology, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX.
authors.forename: Jules
authors.initials: J
authors.lastname: Nde
authors.affiliation: Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, TX.
authors.forename: Raj K
authors.initials: RK
authors.lastname: Pandita
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Straube
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Glen M
authors.initials: GM
authors.lastname: Boyle
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Fares
authors.initials: F
authors.lastname: Al-Ejeh
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.|School of Natural Sciences, Griffith University, Nathan, Brisbane, QLD, Australia.
authors.forename: Purba
authors.identifier: 0000-0002-6863-5438
authors.initials: P
authors.lastname: Nag
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Jessie
authors.initials: J
authors.lastname: Jeffery
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Janelle L
authors.initials: JL
authors.lastname: Harris
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Bain
authors.affiliation: Laboratory of Bioinformatics and Systems Biology, Center of New Technologies, University of Warsaw, Warsaw, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Grzelak
authors.affiliation: Laboratory of Bioinformatics and Systems Biology, Center of New Technologies, University of Warsaw, Warsaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Skrzypczak
authors.affiliation: Department of Biochemistry & Molecular Biology, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Mitra
authors.affiliation: Department of Biochemistry & Molecular Biology, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX.
authors.forename: Norbert
authors.initials: N
authors.lastname: Dojer
authors.affiliation: Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Nicola
authors.initials: N
authors.lastname: Crosetto
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Nicole
authors.initials: N
authors.lastname: Cloonan
authors.affiliation: School of Medicine, University of Queensland, Brisbane, QLD, Australia.|Centre for Clinical Research, Cancer and Neuroscience, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Olivier J
authors.initials: OJ
authors.lastname: Becherel
authors.affiliation: South Australia Pathology and School of Veterinary Science, University of Adelaide, Adelaide, SA, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Finnie
authors.affiliation: Department of Pathology, Cancer Institute, New York University School of Medicine, New York, NY.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Skaar
authors.affiliation: St. Vincent's Institute of Medical Research and Department of Medicine, St. Vincent's Hospital, University of Melbourne, Fitzroy, VIC, Australia; and.
authors.forename: Carl R
authors.initials: CR
authors.lastname: Walkley
authors.affiliation: Department of Radiation Oncology, The Houston Methodist Research Institute, Houston, TX.
authors.forename: Tej K
authors.initials: TK
authors.lastname: Pandita
authors.affiliation: Department of Biochemistry & Molecular Biology, Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX.
authors.forename: Maga
authors.initials: M
authors.lastname: Rowicka
authors.affiliation: Laboratory of Bioinformatics and Systems Biology, Center of New Technologies, University of Warsaw, Warsaw, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Ginalski
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.|School of Medicine, University of Queensland, Brisbane, QLD, Australia.|Department of Haematology, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia.
authors.forename: Steven W
authors.identifier: 0000-0002-8050-6209
authors.initials: SW
authors.lastname: Lane
authors.affiliation: QIMR Berghofer Medical Research Institute, Herston, QLD, Australia.
authors.forename: Kum Kum
authors.identifier: 0000-0001-8650-5381
authors.initials: KK
authors.lastname: Khanna
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000502:physiology*; D002470:Cell Survival / Q000502:physiology; D018899:CpG Islands / Q000502:physiology; D053903:DNA Breaks, Double-Stranded; D042822:Genomic Instability / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: C515022:SSB-1 protein, mouse; C515023:SSB-4 protein, mouse; D050826:Suppressor of Cytokine Signaling Proteins; D016159:Tumor Suppressor Protein p53