Regulation of Human FcεRI α-Chain Gene Expression by Multiple Transcription Factors

Transcriptional regulation of the gene-encoding human FceRI α-chain was analyzed in detail. EMSA revealed that either YY1 or PU.1 bound to the region close to that recognized by Elf-1. The α-chain promoter activity was up-regulated ∼2-fold by exogenously expressed YY1 or PU.1 and ∼7-fold by GATA-1, respectively, in KU812 cells. In contrast, coexpression of GATA-1 with either of PU.1 or YY1 dramatically activated the promoter ∼41- or ∼27-fold, respectively. Especially synergic activation by GATA-1 and PU.1 was surprising, because these transcription factors are known to inhibit the respective transactivating activities of each other. These up-regulating effects of PU.1 and YY1 with GATA-1 were inhibited by overexpression of Elf-1, indicating that Elf-1 serves as a repressor for the α-chain gene expression. Transcriptional regulation of the α-chain gene through four transcriptional factors is discussed.