Document Type

Journal Article

Publication Date

7-1-2015

Journal

PLOS Genetics

Volume

11

Issue

7

Inclusive Pages

e1005346

DOI

10.1371/journal.pgen.1005346

Keywords

Carrier Proteins--genetics; Cell Survival--genetics; DNA Repair--genetics; Hematopoiesis--genetics; Hematopoietic Stem Cells--cytology; Zebrafish Proteins--genetics

Abstract

In vertebrate definitive hematopoiesis, nascent hematopoietic stem/progenitor cells (HSPCs) migrate to and reside in proliferative hematopoietic microenvironment for transitory expansion. In this process, well-established DNA damage response pathways are vital to resolve the replication stress, which is deleterious for genome stability and cell survival. However, the detailed mechanism on the response and repair of the replication stress-induced DNA damage during hematopoietic progenitor expansion remains elusive. Here we report that a novel zebrafish mutantcas003 with nonsense mutation in topbp1 gene encoding topoisomerase II β binding protein 1 (TopBP1) exhibits severe definitive hematopoiesis failure. Homozygous topbp1cas003 mutants manifest reduced number of HSPCs during definitive hematopoietic cell expansion, without affecting the formation and migration of HSPCs. Moreover, HSPCs in the caudal hematopoietic tissue (an equivalent of the fetal liver in mammals) in topbp1cas003 mutant embryos are more sensitive to hydroxyurea (HU) treatment. Mechanistically, subcellular mislocalization of TopBP1cas003 protein results in ATR/Chk1 activation failure and DNA damage accumulation in HSPCs, and eventually induces the p53-dependent apoptosis of HSPCs. Collectively, this study demonstrates a novel and vital role of TopBP1 in the maintenance of HSPCs genome integrity and survival during hematopoietic progenitor expansion.

Comments

Reproduced with permission of PLoS Genetics

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Peer Reviewed

1

Open Access

1