Functional Study of Polymorphism 1888 C>T in the Promoter Region of Human PLUNC Gene.

BACKGROUND

Our previous study showed that a single nucleotide polymorphisms (SNP) of 1888 C>T located at promoter region of human PLUNC gene might affect the susceptibility of nasopharyngeal carcinoma (NPC) in a Chinese population. This study aims to analyze the effect of the genetic variant on PLUNC promoter activity.

MATERIALS AND METHODS

The DNA fragments of the PLUNC promoter region including the SNP 1888 C>T were obtained by polymerase chain reaction (PCR). The recombinant plasmid of the fragment and the pGL3-Enhancer firefly luciferase reporter vector were cloned and identified. Relative luciferase activity (RLA) was measured and electrophoretic mobility shift assay (EMSA) was analyzed.

RESULTS

Luciferase reporter assays demonstrated that luciferase activity of the 1888 T-allele was significantly higher, compared with the C-allele. EMSA experiment proved that the PLUNC gene promoter region SNP 1888 TT genotype had the ability to bind the nucleus protein with the human NPC CEN2 cell, whereas the CC genotype had not.

CONCLUSIONS

SNP 1888 C>T in the promoter region of PLUNC gene might be a functional mutant locus, indicating that individuals carrying SNP 1888 C-C genotype might be more likely to develop NCP due to the reduced expression of the PLUNC gene. Further functional studies on PLUNC genetic variants are warranted to verify our findings.