Dynamic redistribution and inheritance of chromatin:RNA interactions during cell division

During interphase, the nucleus contains a multitude of transcripts that influence the function of chromatin and global structure of the nucleus. Nuclear transcripts include nascent mRNAs in the process of transcription and mRNA processing, spliceosomal RNAs which catalyze mRNA processing, rRNAs that are being transcribed and processed to assemble functional ribosomes, and sno- and scaRNAs that participate in rRNA processing and modification. In addition, there are long noncoding RNAs (lncRNA) that associate with chromatin to control gene expression, or can even influence locus function in the case of centromeres and telomeres. Most of our knowledge of the functions of nuclear RNAs come from studies of interphase cells when the nuclear envelope separates nuclear and cytoplasmic contents. However, during mitosis the nuclear envelope breaks down, resulting in the mixing of nuclear and cytoplasmic components. Much less is known about the regulation and function of nuclear RNAs during mitosis. In this review, we discuss the cell cycle-dependent localization of different categories of RNAs, how the trans-acting factors SAF-A and Ki-67 regulate mitotic RNA localization, and describe how select categories of RNAs are inherited from the previous cell cycle in G1.