This paper describes setting up systems to determine splicing-related protein-RNA interactions; this might be especially useful for confirming whether a particular putatuve splice-regulatory protein binding site is actually involved in modulating splicing. The oligos reported were not Morpholinos, but I expect this system would be compatible with Morpohlinos.
Hybrid splicing minigene and antisense oligonucleotides as efficient tools to determine functional protein/RNA interactions.
Cywoniuk P, Taylor K, Sznajder ŁJ, Sobczak K.
Sci Rep. 2017 Dec 14;7(1):17587. doi: 10.1038/s41598-017-17816-x.