TY - JOUR
T1 - Etv2 is expressed in the yolk sac hematopoietic and endothelial progenitors and regulates Lmo2 gene expression
AU - Koyano-Nakagawa, Naoko
AU - Kweon, Junghun
AU - Iacovino, Michelina
AU - Shi, Xiaozhong
AU - Rasmussen, Tara L.
AU - Borges, Luciene
AU - Zirbes, Katie M.
AU - Li, Tongbin
AU - Perlingeiro, Rita C R
AU - Kyba, Michael
AU - Garry, Daniel J.
PY - 2012/8
Y1 - 2012/8
N2 - During embryogenesis, the endothelial and the hematopoietic lineages first appear during gastrulation in the blood island of the yolk sac. We have previously reported that an Ets variant gene 2 (Etv2/ER71) mutant embryo lacks hematopoietic and endothelial lineages; however, the precise roles of Etv2 in yolk sac development remains unclear. In this study, we define the role of Etv2 in yolk sac blood island development using the Etv2 mutant and a novel Etv2-EYFP reporter transgenic line. Both the hematopoietic and the endothelial lineages are absent in the Etv2 mutant yolk sac. In the Etv2-EYFP transgenic mouse, the EYFP reporter is activated in the nascent mesoderm, expressed in the endothelial and blood progenitors, and in the Tie2+, c-kit+, and CD41+ hematopoietic population. The hematopoietic activity in the E7.75 yolk sac was exclusively localized to the Etv2-EYFP1 population. In the Etv2 mutant yolk sac, Tie2+ cells are present but do not express hematopoietic or endothelial markers. In addition, these cells do not form hematopoietic colonies, indicating an essential role of Etv2 in the specification of the hematopoietic lineage. Forced overexpression of Etv2 during embryoid body differentiation induces the hematopoietic and the endothelial lineages, and transcriptional profiling in this context identifies Lmo2 as a downstream target. Using electrophoretic mobility shift assay, chromatin immunoprecipitation, transcriptional assays, and mutagenesis, we demonstrate that Etv2 binds to the Lmo2 enhancer and transactivates its expression. Collectively, our studies demonstrate that Etv2 is expressed during and required for yolk sac hematoendothelial development, and that Lmo2 is one of the downstream targets of Etv2.
AB - During embryogenesis, the endothelial and the hematopoietic lineages first appear during gastrulation in the blood island of the yolk sac. We have previously reported that an Ets variant gene 2 (Etv2/ER71) mutant embryo lacks hematopoietic and endothelial lineages; however, the precise roles of Etv2 in yolk sac development remains unclear. In this study, we define the role of Etv2 in yolk sac blood island development using the Etv2 mutant and a novel Etv2-EYFP reporter transgenic line. Both the hematopoietic and the endothelial lineages are absent in the Etv2 mutant yolk sac. In the Etv2-EYFP transgenic mouse, the EYFP reporter is activated in the nascent mesoderm, expressed in the endothelial and blood progenitors, and in the Tie2+, c-kit+, and CD41+ hematopoietic population. The hematopoietic activity in the E7.75 yolk sac was exclusively localized to the Etv2-EYFP1 population. In the Etv2 mutant yolk sac, Tie2+ cells are present but do not express hematopoietic or endothelial markers. In addition, these cells do not form hematopoietic colonies, indicating an essential role of Etv2 in the specification of the hematopoietic lineage. Forced overexpression of Etv2 during embryoid body differentiation induces the hematopoietic and the endothelial lineages, and transcriptional profiling in this context identifies Lmo2 as a downstream target. Using electrophoretic mobility shift assay, chromatin immunoprecipitation, transcriptional assays, and mutagenesis, we demonstrate that Etv2 binds to the Lmo2 enhancer and transactivates its expression. Collectively, our studies demonstrate that Etv2 is expressed during and required for yolk sac hematoendothelial development, and that Lmo2 is one of the downstream targets of Etv2.
KW - Endothelial development
KW - Etv2
KW - Etv2 knockout
KW - Hematopoiesis
KW - Transgenesis
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U2 - 10.1002/stem.1131
DO - 10.1002/stem.1131
M3 - Article
C2 - 22628281
AN - SCOPUS:84864347328
SN - 1066-5099
VL - 30
SP - 1611
EP - 1623
JO - STEM CELLS
JF - STEM CELLS
IS - 8
ER -