Previously, we have identified 14 putative downstream target genes of Hoxc8 homeoprotein in F9 murine embryonic teratocarcinoma cells through proteomics analysis. Among those, we tested a possibility of a DNA-k type molecular chaperone, Grp78, as a direct downstream target of Hoxc8, by cloning a 2.4 kb upstream region of murine Grp78 into a reporter plasmid and by testing if Hoxc8 can regulate its expression. We observed that Hoxc8 proteins could transactivate the reporter gene, which was affected by small interference RNAs (siRNAs) against to Hoxc8, suggesting that Grp78 is a novel downstream target of Hoxc8 in vivo.