tokens: When a longer - 714 to + 78 fragment of the PBGD promoter is used , the - 70 GATA mutant still displays erythroid - specific activity and is cis - activated by the 5 ' HS - 2 enhancer , while the - 100 CCACC mutant is completely inactive in the absence or in the presence of the 5 ' HS - 2 enhancer .