POLR2A and systemic lupus erythematosus: In fact, by assessing the transcription factor landscape at the CXorf21 locus, we found significant binding events of RNA polymerase II (POLR2A) at the 3′ SLE-associated region in immune cell types only; corroborating our hypothesis that the observed chromatin looping is necessary for transcriptional regulation (Supplementary Fig. 5).