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Updated: Apr 6, 2026

A Reporter Assay to Analyze Intronic microRNA Maturation in Mammalian Cells
Published on: June 16, 2022
The host Integrator complex acts in transcription-independent maturation of herpesvirus microRNA 3' ends
Mingyi Xie1, Wei Zhang2, Mei-Di Shu1
1Howard Hughes Medical Institute, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA; Department of Molecular Biophysics and Biochemistry, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA;
Abstract:
Herpesvirus saimiri (HVS) is an oncogenic γ-herpesvirus that produces microRNAs (miRNAs) by cotranscription of precursor miRNA (pre-miRNA) hairpins immediately downstream from viral small nuclear RNAs (snRNA). The host cell Integrator complex, which recognizes the snRNA 3' end processing signal (3' box), generates the 5' ends of HVS pre-miRNA hairpins. Here, we identify a novel 3' box-like sequence (miRNA 3' box) downstream from HVS pre-miRNAs that is essential for miRNA biogenesis. In vivo knockdown and rescue experiments confirmed that the 3' end processing of HVS pre-miRNAs also depends on Integrator activity. Interaction between Integrator and HVS primary miRNA (pri-miRNA) substrates that contain only the miRNA 3' box was confirmed by coimmunoprecipitation and an in situ proximity ligation assay (PLA) that we developed to localize specific transient RNA-protein interactions inside cells. Surprisingly, in contrast to snRNA 3' end processing, HVS pre-miRNA 3' end processing by Integrator can be uncoupled from transcription, enabling new approaches to study Integrator enzymology.
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