REGULATED BASAL, INDUCIBLE, AND TISSUE-SPECIFIC HUMAN ERYTHROPOIETIN GENE-EXPRESSION IN TRANSGENIC MICE REQUIRES MULTIPLE CIS DNA-SEQUENCES

Erythropoietin (Epo) gene expression in kidney and liver is inducible by anemia. To localize the sequences necessary for regulated expressio n of the Epo gene, we constructed transgenic mice containing five huma n Epo gene constructs and examined Epo expression under basal conditio ns and with anemia. Mice containing the Epo gene with 0.3 kb of 5' fla nking sequence, 0.7 kb of 3' flanking sequence, and either all introns or only intron I alone were polycythemic, had Epo expression in vario us tissues (including non-Epo-producing tissues), and induction only i n liver. In contrast, mice containing the Epo gene with 8.5 kb of 3' f lanking sequence and either 9.5 or 22 kb of 5' flanking sequence had b asal expression at low levels in appropriate tissues and were less lik ely to be markedly polycythemic. Mice with the smaller of these two co nstructs had induction only in the liver, whereas those with the large r construct had induction in the kidney and liver. These studies indic ate that sequences sufficient for induction in the liver are located i n close proximity to the Epo gene, including the immediate 5' and 3' f lanking sequence and the first intron. They also indicate that sequenc es required for induction in the kidney are located more than 9.5 kb 5 ' to the gene. Furthermore, comparison of these and prior transgenic s tudies suggest that sequences that limit the basal expression of the E po gene are located downstream of the gene. We conclude that multiple cis DNA sequences are required for regulated Epo gene expression. (C) 1995 by The American Society of Hematology.