Oct-1 is responsible for the C-33T polymorphism effect in the IL-4 promoter.
IL-4 is a pleiotropic immunoregulatory cytokine secreted by Th2 subset of CD4(+) Th cells. Several transcription factors (TFs) have been determined with various degrees of certainty to bind the IL-4 promoter and to regulate its expression in human. To investigate the mechanisms responsible for phenotypic effects of the C-33T IL-4 promoter polymorphism, we performed a search of TFs binding to this promoter locus and discriminating the -33C and -33T alleles. In silico searches suggest few factors bind this region. Using an electromobility shift assay we found that Jurkat T cells contained proteins which specifically interacted with oligonucleotide probes, corresponding to the -33 region. Considerable binding differences between C and T alleles were demonstrated using competitive conditions, the proteins bound predominantly with -33C allele. We found that the transcription factor Oct-1 produced the major shifted complex. The binding of Oct-1 was not improved using activated nuclear extracts; however, we observed increases in other shifted complexes upon cell activation. We suppose that Oct-1 occupancy may compete for binding of activator proteins to closely or overlapped binding sites. Our findings suggest that the interplay between Oct-1 and unknown TFs may be responsible for the C-33T polymorphism effects.
Gervaziev
Y V
YV
I.I. Mechnikov's Institute of Vaccines and Sera RAMS, Moscow, Russia. 3457433@bk.ru
Olenina
L V
LV
Krasotkina
J V
JV
Lupatov
A Y
AY
Mazurina
S A
SA
Gervazieva
V B
VB
D001483:Base Sequence; D002457:Cell Extracts; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics*; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1 / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011401:Promoter Regions, Genetic; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002457:Cell Extracts; D050811:Octamer Transcription Factor-1; D015847:Interleukin-4; D013755:Tetradecanoylphorbol Acetate