Fig. 1

University of California Santa Cruz (UCSC) Genome Browser screen shot showing abundant intronic transcription in the TNF gene (a) and in the STAT4 gene (b) within introns. Black bars indicate the region amplified by PCR experiments, as described in “Methods.” c, d Agarose gel images showing qualitative PCR amplification of intronic transcription (ncRNA) in the TNF gene (c) and in the STAT4 gene (d) in neutrophils. N neutrophil RNA not subjected to reverse transcription, R neutrophil RNA subjected to reverse transcription prior to amplification. Neutrophils were isolated from patients with juvenile idiopathic arthritis (JIA) and healthy children (HC). Absence of signal in PCR amplifications that were performed without prior reverse transcription indicates that the signal was not being produced by contaminating DNA