Yin, ShanyeYu, YongReed, Robin2015-08-032015Yin, Shanye, Yong Yu, and Robin Reed. 2015. “Primary microRNA processing is functionally coupled to RNAP II transcription in vitro.” Scientific Reports 5 (1): 11992. doi:10.1038/srep11992. http://dx.doi.org/10.1038/srep11992.2045-2322http://nrs.harvard.edu/urn-3:HUL.InstRepos:17820941Previous studies in vivo reported that processing of primary microRNA (pri-miRNA) is coupled to transcription by RNA polymerase II (RNAP II) and can occur co-transcriptionally. Here we have established a robust in vivo system in which pri-miRNA is transcribed by RNAP II and processed to pre-miRNA in HeLa cell nuclear extracts. We show that both the kinetics and efficiency of pri-miRNA processing are dramatically enhanced in this system compared to that of the corresponding naked pri-miRNA. Moreover, this enhancement is general as it occurs with multiple pri-miRNAs. We also show that nascent pri-miRNA is efficiently processed before it is released from the DNA template. Together, our work directly demonstrates that transcription and pri-miRNA processing are functionally coupled and establishes the first in vivo model systems for this functional coupling and for co-transcriptional processing.en-USJournal Article2015-08-0310.1038/srep11992