Intergenic transcription is not required in Th2 cells to maintain histone acetylation and transcriptional permissiveness at the Il4-Il13 locus

Noncoding RNA transcripts mapping to intergenic regions of the Il4-Il13 locus have been detected in Th2 cells harboring transcriptionally permissive Il4 and ILl3 genes but not in Th1 cells where these genes are repressed. This correlation has given rise to the idea that intergenic transcription may be involved in maintaining the "open" chromatin structure of the Il4-Il13n Th2 cells. We present evidence from real-time RT-PCR, nuclear run on, chromatin immunoprecipitation and 5,6-dichlorobenzimidazole 1-beta-D-ribofuranoside-mediated transcriptional inhibition analyses that argue against this hypothesis. Instead, our results are consistent with an alternative role for intergenic transcription in the maintenance of transcriptional silence in Th1-primed cells.