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. 2008 Feb 12;111(9):4500–4510. doi: 10.1182/blood-2007-09-110569

Figure 4.

Figure 4

Analysis of interaction between etsrp and scl and alk8 signaling pathways. (A-H) scl RNA can rescue myeloid but not vascular cell formation in etsrp morphants as evident from pu.1 and flk1 expression analysis at the 10-somite stage. (A-D) pu.1 expression, anterior view; (E-H) flk1 expression, dorsal view, anterior to the left. (A,E) Control uninjected embryos; (B,F) embryos injected with etsrp MOs; (C,G) scl RNA-injected embryos; (D,H) embryos coinjected with etsrp MOs and scl RNA. Note that the myeloid-specific pu.1 expression is restored in etsrp MO and scl RNA coinjected embryos (D). Also note that the vascular-specific flk1 expression is absent in etsrp MO and scl RNA coinjected embryos in the same experiment (H). (I-P) etsrp RNA can rescue vascular but not myeloid cell formation in scl morphants as evident from pu.1 and flk1 expression analysis at the 8-somite stage. (I-L) pu.1 expression as analyzed by in situ hybridization, anterior view; (M-P) GFP fluorescence in flk1-GFP transgenic embryos, dorsal view, anterior is to the left. (I,M) Control uninjected embryo; (J,N) scl MO-injected embryo; (K,O) etsrp RNA-injected embryo; (L,P) scl MO and etsrp RNA coinjected embryo. Note that etsrp RNA fails to rescue myeloid-specific pu.1 expression in scl morphants (L). Etsrp RNA can restore vascular flk1-GFP expression in the same experiment (P). Flk1-GFP fluorescence in wild-type embryos and scl morphants (M,N) is much weaker and not apparent under the same exposure. (Q-T) etsrp RNA fails to rescue pu.1 expression in alk8 morphants. pu.1 expression analyzed at the 10-somite stage, anterior view, except for panel S, which is anterior-ventral. (Q) Control uninjected embryo; (R) alk8 MO-injected embryo; (S) etsrp RNA-injected embryo; (T) alk8 MO and etsrp RNA coinjected embryo. (U-X) etsrp and constitutively active CA-alk8 RNA synergize in inducing pu.1 expression at the 14-somite stage. Anterior-ventral views except for panel X, which is the ventrolateral view, anterior is to the top. (U) Control uninjected embryo; (V) CA-alk8 RNA-injected embryo; (W) etsrp RNA-injected embryo; (X) CA-alk8 RNA and etsrp RNA coinjected embryo. Images were taken using CV11 stereomicroscope (Zeiss), Axiocam color camera (Zeiss, model 412-312) and Openlab 4.0 software (Improvision). Magnification: 60×.