Splice blocking of zygotic sox31 leads to developmental arrest shortly after Mid-Blastula Transition and induces apoptosis in zebrafish

Here we report that splice blocking morpholinos (Sb MO) against zebrafish sox31 elicit developmental arrest, likely through creating a series of dominant negative splicing variants. Embryos injected with the Sb MO develop normally before the Mid-Blastula Transition (MBT); however, they do not initiate epiboly. Microarray analysis of mRNAs collected at the dome stage revealed that the Sb MO impairs activation of a large set of zygotic genes and reduces degradation of maternal mRNA during MBT. Furthermore, an apoptotic response occurs in Sb morphants at about 6 hpf. SoxB1 family genes including sox31 thus play an essential role for early embryos traversing the transitional stage.

► Splice blocking of sox31 elicits developmental arrest in zebrafish embryos.
► The Sb MO impairs the zygotic gene “up” and maternal mRNA “down” events during MBT.
► The Sb MO of sox31 induces an apoptotic response.