A Graves' disease-associated Kozak sequence single-nucleotide polymorphism enhances the efficiency of CD40 gene translation: a case for translational pathophysiology.
We analyzed the mechanism by which a Graves' disease-associated C/T polymorphism in the Kozak sequence of CD40 affects CD40 expression. CD40 expression levels on B cells in individuals with CT and TT genotypes were decreased by 13.3 and 39.4%, respectively, compared with the levels in CC genotypes (P = 0.012). Similarly, Rat-2 fibroblasts transfected with T-allele cDNA expressed 32.2% less CD40 compared with their C-allele-transfected counterparts (P = 0.004). Additionally, an in vitro transcription/translation system showed that the T-allele makes 15.5% less CD40 than the C-allele (P < 0.001), demonstrating that the effect of the single-nucleotide polymorphism (SNP) on CD40 expression is at the level of translation. However, the SNP did not affect transcription, because the mRNA levels of CD40, as measured by quantitative RT-PCR, were independent of genotype. Therefore, our results may suggest that the C allele of the CD40 Kozak SNP, which is associated with Graves' disease, could predispose to disease by increasing the efficiency of translation of CD40 mRNA.
Jacobson
Eric M
EM
Division of Endocrinology, Box 1055, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, New York 10029, USA. Eric.Jacobson@mssm.edu
Concepcion
Erlinda
E
Oashi
Taiji
T
Tomer
Yaron
Y
D020121:5' Untranslated Regions / Q000235:genetics; D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D019013:CD40 Antigens / Q000235:genetics*; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D006111:Graves Disease / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D020641:Polymorphism, Single Nucleotide; D014176:Protein Biosynthesis / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D014158:Transcription, Genetic / Q000502:physiology; D014162:Transfection
D020121:5' Untranslated Regions; D019013:CD40 Antigens; D012333:RNA, Messenger