Alternative splicing Chromatin Co-transcriptional splicing Kinetic model RNA polymerase II RNA polymerase II-CTD Transcription-splicing coupling alternative RNA splicing article chromatin structure genetic transcription human intron priority journal transcription regulation Alternative Splicing Humans RNA Polymerase II RNA Precursors RNA Splicing RNA precursor RNA splicing RNA transcription RNA translation Transcription, Genetic cancer genetics carboxy terminal sequence carcinogenesis chemical reaction kinetics chromatin