DNA recognition sequence of PAS heterodimers.

1 The names of the recognition sites are indicated: CNS midline enhancer (CME), hypoxia response element (HRE), xenobiotic response element (XRE) and the E box is the recognition site for bHLH proteins. Similar (Sima) is the fly hypoxia inducible factor-α, Spineless (Ss) functions in bristle, leg and antennal development and Period (Per), Timeless (Tim), Clock and Bmal function in circadian rhythms.2 The CGTG core sequences shared by each recognition site are italicized.3 The GCGTG and ACGTG sites are likely low affinity sites for Dys/Tgo [58].