Fig. 9: The model of U2AF-dependent splicing on a conventional-sized intron with a regular PPT and SPF45-dependent splicing on a short intron with a truncated PPT.
From: SPF45/RBM17-dependent, but not U2AF-dependent, splicing in a distinct subset of human short introns
The associated splicing factors with the domain structures and the target sequences of pre-mRNAs are represented schematically. On short intron with truncated PPT (Tr. PPT), U2AF heterodimer is replaced by SPF45 and interacts with SF3b155 (U2 snRNP component) via UHM–ULM binding to promote splicing. Since both U2AF65 and SPF45 can bind to long introns simultaneously via five ULMs in SF3b155, the alternative model that U2AF65 displaces SPF45 in long introns would be impossible.
