A CELLULAR COFACTOR FOR THE CONSTITUTIVE TRANSPORT ELEMENT OF TYPE-D RETROVIRUS

A human nuclear protein that specifically interacts with the constitut ive transport element (CTE) of simian retrovirus was identified as ade nosine 5'-triphosphate-dependent RNA helicase A. This protein could bi nd to functional CTE but not to inactive CTE mutants. The interaction of helicase A with CTE was distinct from previously described helicase activity of this protein. Helicase A shuttled from the nucleus to the cytoplasm in the presence of a transcription inhibitor or in cells tr ansiently overexpressing CTE-containing RNA. In vivo colocalization of helicase A and CTE was observed in experiments that combined in situ hybridization and immunostaining, These results suggest that helicase A plays a role in the nuclear export of CTE-containing RNA.