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Loss of the homologous recombination gene rad51 leads to Fanconi anemia-like symptoms in zebrafish

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Botthof, JG 
Bielczyk-Maczyńska, E 
Ferreira, L 

Abstract

RAD51 is an indispensable homologous recombination protein, necessary for strand invasion and crossing over. It has recently been designated as a Fanconi anemia (FA) gene, following the discovery of two patients carrying dominant-negative mutations. FA is a hereditary DNA-repair disorder characterized by various congenital abnormalities, progressive bone marrow failure, and cancer predisposition. In this report, we describe a viable vertebrate model of RAD51 loss. Zebrafish rad51 loss-of-function mutants developed key features of FA, including hypocellular kidney marrow, sensitivity to cross-linking agents, and decreased size. We show that some of these symptoms stem from both decreased proliferation and increased apoptosis of embryonic hematopoietic stem and progenitor cells. Comutation of p53 was able to rescue the hematopoietic defects seen in the single mutants, but led to tumor development. We further demonstrate that prolonged inflammatory stress can exacerbate the hematological impairment, leading to an additional decrease in kidney marrow cell numbers. These findings strengthen the assignment of RAD51 as a Fanconi gene and provide more evidence for the notion that aberrant p53 signaling during embryogenesis leads to the hematological defects seen later in life in FA. Further research on this zebrafish FA model will lead to a deeper understanding of the molecular basis of bone marrow failure in FA and the cellular role of RAD51.

Description

Keywords

fanconi anemia, stem cells, hematopoiesis, cytokine effects, inflammation

Journal Title

Proceedings of the National Academy of Sciences of the United States of America

Conference Name

Journal ISSN

0027-8424
1091-6490

Volume Title

114

Publisher

National Academy of Sciences
Sponsorship
Cancer Research Uk (None)
Isaac Newton Trust (1523(e))
European Hematology Association (EHA)
European Research Council (677501)
Medical Research Council (MC_PC_12009)
We thank the Sanger Institute Zebrafish Mutation Project for supplying the rad51sa23805 allele; Sebastian Gerety for supplying the tp53zdf1 line; Yvette Hooks for her help with histology; and the Sanger Institute FACS core facility and Charlotte Labalette for their experimental help. This work was supported by Cancer Research UK Grant C45041/A14953 (to A.C.); a core support grant from the Wellcome Trust and Medical Research Council to the Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute; and a European Hematology Association–Jose Carreras Foundation Young Investigator Award and Isaac Newton Trust grant (to A.C.).