Sequence encoding a GAL4::Sp1 driver (amino acids 1-93 of Scer\GAL4 are fused to the Gln rich activation domain, amino acids 132-243, of Mmmm\Sp1). Expression is driven by an Hsp83 promoter fragment from position -880 to +150 and a 900bp SacII-XbaI fragment of bcd 3' UTR.