Characterization of the human mucin 5AC promoter and its regulation by the histone acetyltransferase P300.

Histone acetylation is important in the modification of gene transcription in asthma and is regulated by histone acetyltransferases (HATs). P300 (P300 HAT) is an enzyme that is able to acetylate a wide variety of proteins. The modification of core histones can further regulate gene transcription, cell proliferation and other cell processes. Airway mucus hypersecretion is one of the most serious pathophysiological symptoms of chronic airway inflammatory diseases, and the human mucin 5AC (MUC5AC) gene has been reported to be a major component of respiratory secretions related to asthma and chronic obstructive pulmonary disease. In the present study, the 5' sequence of the human MUC5AC gene with a 1,348‑bp DNA sequence was amplified from human A549 cells genomic DNA by polymerase chain reaction (PCR), and the product of the PCR was sequenced. By promoter deletion analysis, five promoter segments with different lengths were amplified by PCR. The products were identified by DNA sequencing and the six promoter segments were inserted into pGL3‑enhancer vectors. The core promoter area was identified with a series of 5' deletion promoter plasmids using luciferase reporter assays. MUC5AC promoter activity, and the mRNA and protein expression levels of MUC5AC were observed in P300 wild‑type, P300 mutant, P300 small interfering RNA and P300 control groups. The results showed that the core promoter area of MUC5AC was located within the ‑935/+48 region and that P300 reduced the expression of MUC5AC in A549 cells.