Innate Immune Response and Off-Target Mis-splicing Are Common Morpholino-Induced Side Effects in Xenopus

We report on the implications of genetic KO versus MO-mediated KD of the mesoderm-specifying Brachyury paralogues in the Western clawed frog Xenopus tropicalis. While both KO and KD embryos fail to activate the same core gene regulatory network, resulting in virtually identical morphological defects, embryos injected with control or target MOs also show a systemic GC content dependent immune response and many off-target splicing defects. Overall design: Comparison of poly(A) transcriptome between Brachyury null mutants and morphants over two tailbud stages.