RNA polymerase II subunit B32%3B forms dissociable heterodimer with Rpb7p%3B Rpb4/7 dissociates from RNAPII as Ser2 CTD phosphorylation increases%3B Rpb4/7 regulates cellular lifespan via mRNA decay process%3B involved in recruitment of 3'-end processing factors to transcribing RNAPII complex%2C export of mRNA to cytoplasm under stress conditions%3B also involved in translation initiation