Mediator subunit MED1 modulates intranuclear dynamics of the thyroid hormone receptor.

The thyroid hormone receptors (TRs) mediate thyroid hormone (T )-dependent gene expression. The nuclear import and export signals that direct TR shuttling are well characterized, but little is known about factors modulating nuclear retention. We used fluorescence-based nucleocytoplasmic scoring and fluorescence recovery after photobleaching in transfected cells to investigate whether Mediator subunits MED1 and MED13 play a role in nuclear retention of TR.