Hitherto only one RNA target of Hax-1 has been identified: vimentin mRNA (42) . Data from several reports suggest that Hax-1 binding to the hairpin element within the 3 0 UTR of the vimentin transcript plays a role in its localization to the perinuclear cytoplasm (19, 20, 42) . The importance of proper vimentin transcript localization is illustrated by the fact that its misdirection alters cell morphology and motility (43) . The identification of a second RNA target of Hax-1-the hairpin element present in the Pol b transcript-raises the question as to the identity of other mRNA targets of the protein. One may speculate that there is a pool of such mRNAs, especially because vimentin and Pol b are not functionally or evolutionarily related nor are they involved in the same pathway.