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Mutation in the splicing factor zrsr2 disrupts normal hematopoietic development in zebrafish

Wednesday, September 13, 2017 — Poster Session I

12:00 p.m. – 1:30 p.m.
FAES Terrace
NHGRI
DEVBIO-2

Authors

  • EA Broadbridge
  • E Bresciani
  • W Pei
  • L Xu
  • B Carrington
  • M Jones
  • R Sood
  • SM Burgess
  • PP Liu

Abstract

ZRSR2 is a small nuclear ribonucleoprotein necessary for the splicing of U12-type introns, which are present in ~1% of human genes. These genes perform essential cellular functions such as DNA replication, repair, RNA processing, transcription, and translation. ZRSR2 mutations are frequently observed in patients with Myelodysplastic Syndrome, as well as several other hematopoietic malignancies. Zebrafish zrsr2 protein shows 78% similarity to human ZRSR2. Therefore, since the function of ZRSR2 in the hematopoietic system is poorly understood and, to date, there are no animal models available, we decided to use zebrafish as a model to investigate the function of zrsr2 in vivo. By utilizing the CRISPR/cas9 method we targeted zrsr2 exon-7 and generated two mutant lines, one with a deletion of 24bp (zrsr2del24/del24) and the other a deletion of 11bp (zrsr2del11/del11). Both mutations occur N-terminal to all functional domains of zrsr2. zrsr2del11 is predicted to cause loss of function of zrsr2 by generating a frameshift and premature termination. zrsr2del11/del11 showed signs of anemia during embryonic hematopoiesis, but had normal emergence of adult hematopoietic stem cells (HSCs) as shown by a normal expression of the HSC marker c-myb at 36 hours-post-fertilization. However, at later stages they failed to complete HSC development and lacked expression of most definitive hematopoietic markers. Interestingly, preliminary data showed normal production of the myeloid lineage in zrsr2del11/del11 at 3 dpf. Overall, the hematopoietic phenotypes observed in zrsr2del11/del11 zebrafish embryos suggests that we generated a promising model to characterize the role of ZRSR2 in the hematopoietic system in vivo.

Category: Developmental Biology