Loss-of-Function Mutation in tet2 in Zebrafish Leads to Early MDS like Phenotype

Myelodysplastic syndrome (MDS) is a pre-leukemic state characterized by the failure of the bone marrow to produce mature and functional blood cells. Nearly one-third of MDS patients progress to acute myeloid leukemia (AML). AML is the most common form of acute leukemia in adults and accounts for a high level of mortality in pediatric leukemia.Loss-of-function mutations in the Ten-11 Translocation 2 (TET2) gene are implicated in MDS and AML, but evidence that TET2 mutations are also found in healthy individuals as a result of clonal hematopoiesis calls into question the contribution of TET2 to leukemogenesis. Many studies have tried to mutate the DNA binding domain in TET2 both in mouse and zebrafish, but the blood phenotypes observed have been inconsistent.We created a tet2 zebrafish mutant using CRISPR-Cas9 technology, where we deleted 2.1 kb from exon 2, confirmed by cDNA analysis. A recent publication suggests the importance of Ser99 in the stability of the TET2 protein (Wu et al., 2018) and this conserved serine residue is contained in the region of deletion in our zebrafish tet2 mutant.These tet2 mutant fish were incrossed to create a maternal-zygotic mutant with no tet2 expression. Importantly, quantitative PCR demonstrated that there was no compensatory effect from tet1 and tet3 in the context of tet2 loss.Whole mount in situ hybridization performed on 24-48h tet2 mutant zebrafish embryos provided evidence of a significant reduction of early and mature myeloid and eryt...
Source: Blood - Category: Hematology Authors: Tags: 101. Red Cells and Erythropoiesis, Structure and Function, Metabolism, and Survival, Excluding Iron: Poster II Source Type: research