Recursive splicing occurs with a delay after transcription.

(A) Percent Recursive Splicing (PRS) is defined as the percentage of junction reads that support the intermediate product of recursive splicing. (B) A schematic diagram to show the definition of co-transcriptional and post-transcriptional recursive splicing. For co-transcriptional recursive splicing, the recursive splicing finished before the entire gene was transcribed (top panel), while in post-transcriptional recursive splicing, recursive splicing started after the gene was transcribed (bottom panel). (C) The landscape of recursive splicing during transcription in PA1 cells. (Left) Each row is an RS event. All RS events are clustered into four classes according to their onset time for recursive splicing and sorted within each class by PRS. (Right) The table lists the counts and percentages of RS intron with post-transcriptional or co-transcriptional recursive splicing. For some RS events, we could not determine whether they were post- or co-transcriptional due to the lack of time resolution. (D) PRS dropped progressively after the onset of recursive splicing. Class II (left panel) and III (right panel) introns are shown and the median PRS time course is shown as purple lines. The boxplots show correlation coefficients between the PRS time course of individual RS events and the median time course.