Patent ID: 7186529

Claim:
DNA construct for activating an endogenous EPO gene in a human cell, comprising: (i) two flanking DNA sequences which are homologous to regions of the human gene locus selected from 5′-untranslated sequences, exon 1 and intron 1, in order to permit a homologous recombination, a modified sequence being present in the range of exon 1, coding for the amino acids: Met-X1-X2-X3 wherein X 1 is Gly or Ser, X 2 is Ala, Val, Leu, Ile, Ser or Pro, and X 3 is Pro, Arg, Cys or His, provided that X 1 -X 2 -X 3 is not the sequence Gly-Val-His, (ii) a positive selection marker gene, and (iii) a heterologous expression control sequence which is active in a human cell.