Deletion of Stk40 impairs definitive erythropoiesis in the mouse fetal liver

Abstract

The serine threonine kinase Stk40 has been shown to involve in mouse embryonic stem cell differentiation, pulmonary maturation and adipocyte differentiation. Here we report that targeted deletion of Stk40 leads to fetal liver hypoplasia and anemia in the mouse embryo. The reduction of erythrocytes in the fetal liver is accompanied by increased apoptosis and compromised erythroid maturation. Stk40 − / − fetal liver cells have significantly reduced colony-forming units (CFUs) capable of erythroid differentiation, including burst forming unit-erythroid, CFU-erythroid (CFU-E), and CFU-granulocyte, erythrocyte, megakaryocyte and macrophage, but not CFU-granulocyte/macrophages. Purified Stk40 − / − megakaryocyte-erythrocyte progenitors produce substantially fewer CFU-E colonies compared to control cells. Moreover, Stk40 − / − fetal liver erythroblasts fail to form normal erythroblastic islands in association with wild type or Stk40 − / − macrophages, indicating an intrinsic defect of Stk40 − / − erythroblasts. Furthermore, the hematopoietic stem and progenitor cell pool is reduced in Stk40 − / − fetal livers but still retains the multi-lineage reconstitution capacity. Finally, comparison of microarray data between wild type and Stk40 − / − E14.5 fetal liver cells reveals a potential role of aberrantly activated TNF-α signaling in Stk40 depletion induced dyserythropoiesis with a concomitant increase in cleaved caspase-3 and decrease in Gata1 proteins. Altogether, the identification of Stk40 as a regulator for fetal erythroid maturation and survival provides new clues to the molecular regulation of erythropoiesis and related diseases.

N6-methyladenosine mRNA marking promotes selective translation of regulons required for human erythropoiesis

“…RPS19 encodes a ribosomal protein that when heterozygous for a loss of function mutation causes DBA 70 . STK40 codes for a serine threonine kinase required for definitive erythropoiesis just after the MEP state in the fetal mouse liver, similar to our m 6 A-MTase inhibition phenotype in hHSPCs 55 . The other genes have not been previously implicated in erythropoiesis, including: BRD7 , a member of the bromodomain-containing protein family implicated in tumor suppression of p53 and PI3K pathways 71,72 ; CXXC1 , which encodes a key regulator of H3K4 histone methylation, cytosine methylation, cellular differentiation, and vertebrate development 73 ; and TADA2B , which encodes a transcriptional adapter for transcriptional activation factors 74 .…”

“…Except for BRD7 and TADA2B , each of these genes has known erythroid-related functions (Supplementary Data 5). For example, Pabpc4 has been shown to bind to mRNAs associated with erythroid differentiation in mouse leukemia cells and is required for maintaining the steady-state mRNA levels of a subset of these, including CD235a/GYPA mRNA 54 , while Stk40 deletion leads to anemia in mouse embryos characterized by a reduction in progenitors capable of erythroid differentiation 55 . Further validation of BRD7, CXXC1, PABPC1, PABPC4, STK40, and TADA2B by Western blot showed that their steady-state protein levels decreased after WTAP KO (Fig.…”

N6-methyladenosine mRNA marking promotes selective translation of regulons required for human erythropoiesis

“…RPS19 encodes a ribosomal protein that when heterozygous for a loss of function mutation causes DBA 73 . STK40 codes for a serine threonine kinase required for definitive erythropoiesis just after the MEP state in the fetal mouse liver, similar to our m 6 A-MTase inhibition phenotype in hHSPCs 54 . The other genes have not been previously implicated in erythropoiesis, including: BRD7, a member of the bromodomain-containing protein family implicated in tumor suppression of p53 and PI3K pathways 75,76 ; CXXC1, which encodes a key regulator of H3K4 histone methylation, cytosine methylation, cellular differentiation, and vertebrate development 77 ;…”

“…Critically, except for BRD7 and TADA2B, each of these genes has known erythroid-related functions (Supplementary Table 5). For example, PABPC4 has been shown to bind to mRNAs associated with erythroid differentiation in mouse leukemia cells and is required for maintaining the steady-state mRNA levels of a subset of these, including CD235a/GYPA mRNA 53 , while Stk40 deletion leads to anemia in mouse embryos characterized by a reduction in progenitors capable of erythroid differentiation 54 . Further validation of BRD7, CXXC1, PABPC1, PABPC4, STK40, and TADA2B by Western blot showed that their steady-state protein levels decreased after WTAP KO, supporting the ribosome profiling results ( Fig.…”

Synthetic dysmobility screen unveils an integrated STK40-YAP-MAPK system driving cell migration

“…We first dissected the role of STK40 by altering functions and locations of STK40 proteins and examining their effects on FA. STK40 was reported to regulate cell differentiation as a putative nuclear kinase (19,(25)(26)(27) as well as to maintain protein stability as a cytoplasmic pseudo-kinase (28,29). Thus, we want to know either STK40 location or kinase activity determined FA remodeling.…”