2Moscow Institute of Physics and Technology, Department of Molecular and Biological Physics, 141701 Dolgoprudny, Moscow Region, Russia
3Lomonosov Moscow State University, Faculty of Biology, 119991 Moscow, Russia
4Vavilov Institute of General Genetics, Russian Academy of Sciences, 119333 Moscow, Russia
5Institute of Mathematical Problems of Biology, Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
* To whom correspondence should be addressed.
Received July 13, 2018; Revision received September 4, 2018
CD40 receptor is expressed on B lymphocytes and other professional antigen-presenting cells. The binding of CD40 to its ligand CD154 on the surface of T helper cells plays an important role in the activation of B lymphocytes required for production of antibodies, in particular, against autoantigens. Association of several single nucleotide polymorphisms (SNPs) located in the non-coding areas of human CD40 locus with the elevated risk of autoimmune diseases has been demonstrated. The most studied of these SNPs is rs4810485 located in the first intron of the CD40 gene. Expression of the CD40 gene in B lymphocytes of donors homozygous for the common allelic variant of this polymorphism (G) is higher than in B cells from donors carrying the minor (T) variant. We investigated the enhancer activity of this fragment of the CD40 locus in human B cell lines and showed that it is independent on the rs4810485 alleles. However, the minor allelic variants of the rs4810485-linked SNPs rs548231435 and rs115662534 were associated with a significant decrease in the activity of the CD40 promoter due to the impairments in the binding of EBF1 and STAT1 transcription factors, respectively.
KEY WORDS: autoimmune diseases, polymorphism, CD40, transcription regulation