Isolation and sequencing of AGO-bound RNAs reveals characteristics of stem-loop processing in vivo

ABSTRACT: MicroRNA precursors (pre-miRNAs) are short hairpin RNAs that are rapidly processed into mature microRNAs (miRNAs) in the cytoplasm. Due to their low abundance in cells, sequencing-based studies of pre-miRNAs have been limited. We successfully enriched for and deep sequenced pre-miRNAs in human cells by capturing these RNAs during their interaction with Argonaute (AGO) proteins. Using this approach, we detected > 350 pre-miRNAs in human cells and > 250 pre-miRNAs in a reanalysis of a similar study in mouse cells. We uncovered widespread trimming and non-templated additions to 3’ ends of pre-miRNAs and mature miRNAs. Additionally, we identified novel AGO2-cleaved pre-miRNAs and created an index for microRNA precursor processing efficiency. This analysis revealed a subset of pre-miRNAs that produce low levels of mature miRNAs despite abundant precursors, including an annotated miRNA in the 5’ UTR of the DiGeorge syndrome critical region 8 (Dgcr8) mRNA transcript. This led us to search for other AGO-associated stem-loops originating from other mRNA species, which identified hundreds of putative pre-miRNAs derived from mRNA sequences in both the mouse and human transcriptomes. Intriguingly, we found that iron responsive elements in ferritin heavy and light chain mRNAs are processed into AGO-associated stem-loops in both mouse and humans but do not produce functional small RNAs. In summary, we provide a wealth of information on mammalian pre-miRNAs, and identify novel microRNA and microRNA-like elements localized in mRNAs.

ORGANISM(S): Homo sapiens

PROVIDER: GSE71710 | GEO | 2016/07/30

SECONDARY ACCESSION(S): PRJNA291872

REPOSITORIES: GEO