Bodacious TATAs—Regulation of Eukaryotic Genes

The same pattern holds true for most eukaryotic genes, but with a lot more complexity. (Recall that eukaryotes are organisms which, unlike bacteria, package their genetic material within nuclei.) Many of the genes rapidly expressed by eukaryotes—which happen to be the genes we know the most about because they’re easiest to work with—have a region just upstream from the start site, called the TATA box. As you could probably noodle out for yourself, the TATA box is so-called because it contains the sequence T-A-T-A. This site is evolutionarily highly conserved—meaning we’ve been using it since we were yeasts. It’s very specific—if you go in and change (mutate) one of the nucleotides it doesn’t work very well. It’s so good at cranking up transcription that molecular biologists routinely splice a TATA box, or something like it, onto genes they want to express at high rates in vitro, and viruses have spliced the TATA box into many of their own genes so they can make viral proteins at a higher rate and kill you even faster.