Identification of the elements regulating the expression of the phospholipase C delta1

Recently we cloned the phospholipase C deltal (PLC-delta1) promoter region and found that PLC-delta1 is selectively expressed in several tissues. In order to establish the common and cell-type specific transcriptional elements, 1.8 kilobase of the 5'-flanking region of PLC-delta1 was characterized in several cell lines. A transient transfection assay of the -1787-Luc construct in several cell lines demonstrated the potential transcriptional enhancement of reporter activities in the neuroblastoma cell [SK-N-BE(2)C] and kidney cell lines (Cos-7), but not in liver cell lines (Chang liver cell). Transient transfection assays of a series of 5' --> 3' deletion constructs of the PLC-delta1 promoter and electronic mobility shift assays suggested that the E-box and HFH3 binding sites are cell-type specific elements, and that Sp-1 is a major transcriptional activator of a majority of cell lines. Our findings, therefore, indicate that the combination of several elements within the 5'-flanking region of the PLC-delta1 gene dictates its restricted expression in several cell lines.