Functional impact of endotoxin receptor CD14 polymorphisms on transcriptional activity
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- 作者：Jasmin Mertens ; Rusudan Bregadze ; Ashham Mansur ; Eva Askar ; Heike Bickeb?ller ; Giuliano Ramadori and Sabine Mihm
- 关键词：SNP ; LPS ; Gene polymorphism ; Gene expression ; Innate immunity
- 刊名：Journal of Molecular Medicine
- 出版年：2009
- 出版时间：August, 2009
- 年：2009
- 卷：87
- 期：8
- 页码：815-824
- 全文大小：572.7 KB
文摘
The polymorphism rs2569190 within the CD14 endotoxin (lipopolysaccharide, LPS) receptor gene is associated with various disease conditions that are assumed to rely on endotoxin sensitivity. In vitro experiments suggest that the T allele sensitizes the host for exogenous or endogenous LPS via an enhanced CD14 expression. To prove the impact of this single nucleotide polymorphism in its natural genomic context in vivo, two parameters of gene transcription were analyzed in peripheral blood mononuclear cells (PBMC) from single healthy individuals: (a) recruitment of RNA polymerase II by haplotype-specific chromatin immunoprecipitation and (b) the relative amount of transcripts by allele-specific transcript quantification (ASTQ). RNA polymerase II was found to be twice as much bound to the most prevalent haplotype, C-T-C-G, the only one carrying a T at the position rs2569190 of interest. ASTQ employing two independent read-out assays revealed, however, similar transcript numbers originating from C-T-C-G and non-C-T-C-G haplotypes. Total CD14 mRNA levels from freshly isolated PBMC, moreover, were neither related to donors’ geno- nor haplogenotypes. Our data argue for a functional impact of the rs2569190 polymorphism in terms of a stronger transcription initiation on T allele gene variants even if preferential allele-specific binding does not result in an increase in transcript numbers. Endotoxin sensitivity associated with this genetic variation appears not to rely solely on a cis-acting regulatory impact of rs2569190 on CD14 gene transcription in PBMC.