The QA repeat domain of TCERG1 mediates its inhibitory effect towards C/EBPα and the ability of TCERG1 to be relocalized in the nucleus (946.6)

Previously we showed that TCERG1 inhibits the growth arrest and transactivation functions of C/EBPα, through a mechanism that requires the relocalization of TCERG1 to sites of C/EBPα occupancy in the nucleus. TCERG1 contains a unique QA repeat domain, for which no function has been assigned, as well as 3 WW domains within the N-terminal half of TCERG1 which has been shown previously to mediate its relocalization. These domains were explored for their roles in mediating the inhibitory and relocalization activities of TCERG1. While mutations of the WW domains were without effect, deletion of the QA repeat domain in TCERG1 prevented its relocalization in the nucleus (assessed by confocal microscopy), and abrogated its ability to repress both the growth arrest and transactivation functions of C/EBPα. Reducing the number of QA repeats from 38 to 20 had no impact on the activities of TCERG1, while further reduction to 10 resulted in a significant loss of relocalization ability and inhibitory activity towards C/...