Transcription factor that is involved in activation of anaerobic genes such as DAN/TIR cell wall mannoprotein genes and YML083c. Appears to bind to anaerobic response elements (AR1) with the consensus sequence 5'-TCGTTYAG-3' present in the promoter regions of DAN/TIR genes. Involved in sterol uptake and regulation of the sterol biosynthesis. Binds to sterol regulatory elements (SRE) with the consensus sequence 5'-TCGTATA-3' present in ERG2 and ERG3 promoters. May be involved in down-regulation of CWP2 during anaerobic adaptation. Induced by anaerobic conditions, hypoxia and cold. Repressed by heme. Present with 752 molecules/cell in log phase SD medium. ECM22 and UPC2 (in combination) null mutants are not viable.