protein import into nucleus obsolete splicing factor protein import into nucleus true The reason for obsoletion is that all proteins are imported into the nucleus via the same mechanism, so the import of individual proteins should be captured with extensions or by GO-CAM models. OBSOLETE. The directed movement of a pre-mRNA splicing factor from the cytoplasm into the nucleus, across the nuclear membrane. GO:0035048 splicing factor protein transport from cytoplasm to nucleus biological_process splicing factor protein-nucleus import