|
|
| |
Fig. 5. Xisl-1 is required for normal heart development. (A) At early tadpole stages gross morphological heart defects are clearly seen in whole embryos that have been injected with 20 ng islMO (arrow); dotted line demarcates the heart in the WT embryo. Embryos exhibit an enlarged pericardial cavity and in the most severe cases the heart is reduced to a remnant of beating tissue. About 80% of the islMO injected embryos have heart defects (upper bar graph). These defects were further qualified (lower bar graph). (B) Hearts were dissected from st. 42/43 embryos that have been injected with either islMO or control MO (CMO) to better visualize the morphological defects. In addition to the obvious phenotype of an unlooped heart tube, there are cases when the heart does undergo looping however it is smaller compared to a normal heart. Smaller hearts were measured as indicated in the cartoon and the sizes are presented in μm total length in the bar graph. (C) At earlier stages a heart phenotype in whole embryos injected with islMO is visible by the reduced staining for TnIc. Vibratome sections show that the heart tube is reduced in size and fails to loop as a result of Xisl-1 loss-of-function. Dotted lines depict section plane. a: atria; oft: outflow tract; v: ventricle. |
