Imaging transcription elongation dynamics by new technologies unveils the organization of initiation and elongation in transcription factories
Hiroshi Kimurâ, Yuko Sato
Abstract
In mammalian cells, RNA polymerase II (RNAP2)-mediated transcription occurs in numerous foci in the nucleus. Transcription foci detected by RNAP2 activity have often been called transcription "factories". Recent super-resolution microscopy techniques have revealed clustering and focus formation of RNAP2 in living cells, depending on phosphorylation states of repeats in its C-terminal domain (CTD). The differentially phosphorylated initiation and processive elongation forms of RNAP2 have also been tracked using live-cell probes derived from phosphorylation-specific antibodies. Recent live cell observations have detected spatially separated initiation and elongating RNAP2 foci, suggesting the presence of transcription initiation and elongation factories.