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Figure 1. CST Is Required for Vertebrate Heart Development(A) Predicted schematic representation of CSTα and CSTβ proteins; nuclear localization signal (yellow), zinc finger repeats (red), serine-rich region (red).(B–F) Whole-mount in situ analysis of Stage 27 (early tailbud), Stage 32 (tailbud), and Stage 36 (early tadpole) embryos using a Cst-specific probe common to Cstα and Cstβ. ([B], lateral view with anterior to the left; [C and D] ventral and dorsal views, respectively, with anterior to the top). (D and F) Transverse sections of whole-mount in situ Stage 36 embryos through (D) the heart and (F) the hindbrain: hindbrain (hb), somites (s), heart primordium (hp), heart (h), myocardium (m), endocardium (en), commissural neurons (c).(G–J) Representative (G and I) control MO and (H and J) CstMO embryos. (G) Stage 32 control MO and (H) CstMO embryos are indistinguishable. (I) Stage 41 control MO and (J) CstMO embryos. CST-depleted embryos present with dorsal fin edema and no gross ventral region abnormalities.(K) RT-PCR analysis of Stage 42 tadpoles injected at the one-cell stage with the CstMO demonstrating inhibition of proper slicing of Cst pre-mRNA. Control MO (Con MO) and 5-mismatch MO (5-mis MO) are negative controls.(L) Whole-mount MHC antibody staining of tadpole Stage 37 CST-depleted embryos (lateral views with anterior to the left); inflow tract (i), ventricle (v), outflow tract (o). Scale bars: (B–C) = 0.5 mm, (G) = 1 mm, (D and L) = 100 μm. |
