p29, a novel GCIP-interacting protein, localizes in the nucleus

GCIP, a newly identified cyclin D-interacting protein, was found to reduce the phosphorylation of retinoblastoma protein and inhibit E2F1-mediated tra nscriptional activity. To explore more GCIP interacting proteins, the yeast two-hybrid screening using GCIP as st bait protein was performed. One nove l gene, p29, was demonstrated to associate with GCIP in the yeast two-hybri d method and in vitro GST pull-down assay. Multiple tissue Northern blot an alysis showed. that p29 was abundantly expressed in the heart, skeletal mus cle, and kidney relative to other tissues. The transient expression of HA-t agged p29 in HeLa cells localized in the nucleus. Taken together, we have i solated a novel protein, p29, which may be involved in the functional regul ation of GCIP. (C) 2000 Academic Press.