ABUNDANT EXPRESSION OF ERYTHROID TRANSCRIPTION FACTOR P45 NF-E2 MESSENGER-RNA IN HUMAN PERIPHERAL GRANULOCYTES

Transcription factor NF-E2 is crucial for regulation of erythroid-spec ific gene expression. p45 subunit of NF-E? contains a basic-leucine zi pper domain and dimerizes with the small Maf family protein to form fu nctional NF-E2 complex. While p45 expression was shown to be restricte d to erythroid cells, megakaryocytes and mast cells in hematopoietic l ineage, we found in this study that p45 mRNA is abundantly transcribed in the granulocyte fraction of human peripheral blood cells. As neutr ophils occupy approximately 92% of the cells in this fraction, the cel ls expressing p45 is most likely to be neutrophils. p45 mRNA is also e xpressed in HL-60 promyelocytes, albeit the expression level is much l ower than that of the granulocyte fraction. HL-60 cells were found to express mafK mRNA, indicating the presence of genuine NF-E2, complex i n the cells. Although p45 mRNA is transcribed from two different promo ters, aNF-E2 promoter and fNF-E2 promoter, in erythroid and megakaryoc ytic lineage cells, p45 mRNA is transcribed only from aNF-E2 promoter. The expression of p45 mRNA in the neutrophils declined rapidly after transfer of the cells to in vitro culture and G-CSF could not sustain the expression from the down-regulation, suggesting the E2 may also pa rticipate in the regulation of neutrophil-specific gene expression. (C ) 1996 Academic Press, Inc.