Polymorphisms in the IL-6 receptor (IL-6R) gene: strong evidence that serum levels of soluble IL-6R are genetically influenced.
We have investigated the association of the recently identified IL6R polymorphisms with the serum levels of soluble IL-6 receptor (sIL-6R). sIL-6R is generated by shedding of the membrane-bound receptor (IL-6Ralpha) or alternative mRNA splicing. In total, 115 healthy volunteers were genotyped, with 70 of them analyzed for sIL-6R levels. Using the PCR/RFLP methods, two important polymorphic sites were selected for genotyping: the 48892A/C (D358A) in exon 9 and the -183G/A in the promoter region. In exon 9, C allele carriers had higher sIL-6R level (P<0.0001) showing that this sequence variation, which corresponds to the proteolytic cleavage site of IL-6Ralpha, strongly influences the serum sIL-6R levels. In the promoter region, G allele carriers had lower sIL-6R levels (P<0.0082) compared with the A allele carriers. This could be attributed to the linkage disequilibrium (D'=0.54, chi2=51.3, P<0.0001) between the -183G/A and the 48892A/C gene polymorphisms.
Division of Periodontology, Department of Oral Biological Science, Niigata University, Graduate School of Medical and Dental Sciences, Niigata, Japan.
J C
JC
Galicia
H
H
Tai
Y
Y
Komatsu
Y
Y
Shimada
K
K
Akazawa
H
H
Yoshie
D000328:Adult; D000368:Aged; D017398:Alternative Splicing; D004247:DNA / Q000032:analysis; D005091:Exons / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D019947:Receptors, Interleukin-6 / Q000097:blood* / Q000235:genetics*
D012333:RNA, Messenger; D019947:Receptors, Interleukin-6; D004247:DNA