Expression of a 839bp fragment of Mmus\Hoxb9 cDNA encoding the entire 672bp open reading frame is driven by an Hsp70 fragment from position -225 to +65. Adh 3' flanking sequence contain nucleotides +1763 to +2502 and includes the polyadenylation site. Hsp70 and Adh sequences are present in "pHSBJ".