If our genes are so similar, what really makes a eukaryote different from a prokaryote, or a human from E. coli? The answer lies in the difference in gene expression and regulation used.

Inactivation of Sp1 by treatment with EDTA and recovery of DNA binding activity by addition of Zn(ll). The footprinting reactions contained no Sp1 (lane l); untreated Sp1 (lane 2); Sp1 + EDTA (lane 3) ...