TBP facilitates RNA Polymerase I transcription following mitosis.

The TATA-box binding protein (TBP) is the sole transcription factor common in the initiation complexes of the three major eukaryotic RNA Polymerases (Pol I, II and III). Although TBP is central to transcription by the three RNA Pols in various species, the emergence of TBP paralogs throughout evolution has expanded the complexity in transcription initiation. Furthermore, recent studies have emerged that questioned the centrality of TBP in mammalian cells, particularly in Pol II transcription, but the role of TBP and its paralogs in Pol I transcription remains to be re-evaluated.

Heat shock transcription factors demonstrate a distinct mode of interaction with mitotic chromosomes.

A large number of transcription factors have been shown to bind and interact with mitotic chromosomes, which may promote the efficient reactivation of transcriptional programs following cell division. Although the DNA-binding domain (DBD) contributes strongly to TF behavior, the mitotic behaviors of TFs from the same DBD family may vary. To define the mechanisms governing TF behavior during mitosis in mouse embryonic stem cells, we examined two related TFs: Heat Shock Factor 1 and 2 (HSF1 and HSF2).

Visualizing Transcription Factor Binding on Mitotic Chromosomes Using Single-Molecule Live-Cell Imaging.

For over two decades, scientists have observed that most transcription factors (TFs) become excluded from mitotic chromosomes of mammalian cells undergoing cell division. The few TFs that were observed to remain bound to chromosomes have been termed mitotic bookmarkers and were predicted to play important roles in reestablishing transcription after mitosis. Using live-cell imaging of endogenous TFs in mouse embryonic stem cells, we discovered that the observed exclusion from mitotic chromosomes is largely a result of formaldehyde cross-linking and that in fact, most TFs bind to mitotic chromosomes throughout mitosis.