Transcription profiling by array of mouse CD4+ T cells mutant for Sle1a.1

Sle1a.1 is part of the Sle1a lupus susceptibility locus which results in the production of activated and autoreactive CD4+ T cells as well as a reduction in the peripheral regulatory T cell (Treg) pool. Sle1a.1 CD4+ T cells showed a defective response to retinoic acid (RA) expansion of TGFβ-induced Tregs. At the molecular level, Sle1a.1 corresponds to an increased expression of a novel splice isoform of Pbx1, Pbx1-d. Pbx1-d over-expression is sufficient to induce an activated/inflammatory phenotype in Jurkat T cells, and to decrease their apoptotic response to RA. PBX1-d is expressed more frequently in lupus patients than in healthy controls, and its presence correlates with an increased memory T cell population. These findings indicate that Pbx1 is a novel lupus susceptibility gene that regulates T cell activation and tolerance. Total RNA from CD4+ T cells from C57BL/6 (B6) and B6.Sle1a.1 (Sle) mice was isolated, with 4 biological replicates each. Gene expression data from C57BL/6 mice were compared with data from B6.Sle2c1 mice.