This project is to investigate the relative promoter strengths of various cloned mammalian promoter regions in human cell types of particular interest to the research program of LHC: normal bronchial fibroblasts, mesothelial cells and bronchial epithelial cells, as well as the recently constructed immortalized mesothelial and bronchial cell lines. The assayed promoter/enhancer regions included those from the Rous sarcoma virus (RSV) long terminal repeat (LTR), SV40 virus, Moloney sarcoma virus (MSV) LTR, and adenovirus major late promoter (MLP) with or without SV40 enhancer sequences, HTLV-I LTR or HIV LTR with or without their respective trans-activating proteins, metallothionien with or without cadmium, and mouse mammary tumor virus (MMTV) LTR with and without dexamethasone. The sequences were assayed for their promoter/enhancer activity using the chloramphenicol acetyl transferase (CAT) assay system. In the immortalized lines, SV40-enhanced adenovirus MLP, transactivated HTLV-I LTR and transactivated HIV LTR were highly active. Under the conditions of the assay, the metallothionien promoter was measurably active, but not inducible by cadmium, and MMTV was inducible but showed weak activity. These promoter/enhancer regions are now being tested in normal cells. The very high level of expression by the enhanced adeno-5 MLP and the HTLV-LTR promoters will facilitate construction of vectors for efficient expression of genes in these human cells.
