The interaction for the single positive clone encoding for the terminal 622 bp of the rat Hax-1 gene (Hax-1-C) was tested for growth on 25 mM 3-AT medium without histidine and using the b-gal plate test. The IRE/IRP interaction served as positive control, while transformation with empty vectors as well as single transformants of tested constructs represented negative controls. Hax-1 localizes in mitochondria, but also in the nuclear matrix