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which could recruit Brd4,31-34 whereas Brd4 could recruit DOT1L complex and p-TEFb complex to increase p-TEFb- dependent phosphorylation of pol II CTD and stimulate transcription from promoters that have promoter-proxi- mal pausing.35-37 Such enhanced pol II elongation could result in the upregulation of a subset of genes including Myc, which controls the balance of quiescence and differ- entiation in HSCs.
Discussion
In this study, we generated a novel conditional knock- out allele (Setd2Δ/Δ). These mice manifested leukopenia, macrocytic anemia, increased platelet, and erythroid dys- plasia in BM, which are comparable to the phenotypes of myelodysplastic syndromes (MDS) associated with isolat- ed del(5q). It has been reported that rare SETD2 mutations
AB
CD
EF
Figure 7. Setd2Δ/Δ deficiencies could be partially rescued by super elongation complex-related inhibitors. (A and B) Treatment of c-Kit+ bone marrow (BM) cells from Setd2f/f/Vav1-Cre mice with JQ1 500nM, EPZ-5676 1uM, BAY 1143572 400 nM for 24 h (h). Then cells were collected to determine the proteins levels of H3K36me1/2, H3K4me3, H3K79me2, H3K27me3, H3, RNA pol II (Ser2P), pol II (Ser5P), Gata1, Gata3, Myc, and β-actin by immunoblotting. (C and D) Flow cytometry analysis of drug- treated c-kit+ cells from Setd2f/f and Setd2f/f/Vav1-Cre mice with Annexin V and 7-AAD. Gating strategy is shown in one representative FACS blot per genotype. Summary of statistical analyses showed decreased distribution into AnnexinV positive fraction in drug-treated groups. Representative data were from 3 independent experiments. (Setd2f/f=6 and Setd2f/f/Vav1-Cre=12). (E and F) Flow cytometry analysis of drug treated c-kit+ cells from Setd2f/f and Setd2f/f/Vav1-Cre mice with Ki67 and Hoechst blue. Gating strategy is shown in one representative FACS blot per genotype. Summary of statistical analyses showed increased distribution into G0 fraction in drug-treated groups. Representative data are from 3 independent experiments; (Setd2f/f=6 and Setd2f/f/Vav1-Cre=12).
haematologica | 2018; 103(7)