CPSF6 and glioblastoma: For some mRNA, shortened 3′UTRs will lead to increased protein production, as has also been shown for some 3′UTRs shortened in glioblastoma cell lines that have naturally reduced CFIm.157, 156 In an auto-regulatory loop, CFIm68 provides itself with dosage control through two PASs in the 3′ UTR of its own mRNA; high cellular CFIm68 levels will recruit CPSF to the distal PAS and so generate a long 3′UTR with mRNA-destabilising elements that will gradually lower cellular CFIm68 levels.