Cycling in the nucleus: regulation of RNA 3′ processing and nuclear organization of replication-dependent histone genes

• Histone locus bodies coordinate assembly of transcription and 3′ processing complexes. • Histone gene transcription induces chromatin changes that favor mRNA 3′ processing. • Cyclic control of a histone processing factor that uses proteins of polyA machinery. • U7 snRNP represses histone gene transcription outside of S phase. • Links between histone gene expression, DNA damage, cell proliferation and diseases. The histones which pack new DNA during the S phase of animal cells are made from mRNAs that are cleaved at their 3′ end but not polyadenylated. Some of the factors used in this reaction are unique to it while others are shared with the polyadenylation process that generates all other mRNAs. Recent work has begun to shed light on how the cell manages the assignment of these common components to the two 3′ processing systems, and how it achieves their cell cycle-regulation and recruitment to the histone pre-mRNA. Moreover, recent and older findings reveal multiple connections between the nuclear organization of histone genes, their transcription and 3′ end processing as well as the control of cell proliferation.