Related Experiment Video

Updated: Oct 3, 2025

Chemical Triphosphorylation of Oligonucleotides
13:19

Chemical Triphosphorylation of Oligonucleotides

Published on: June 2, 2022

3.6K

Flexible pri-miRNA structures enable tunable production of 5' isomiRs

Xavier Bofill-De Ros1, Zhenyi Hong2, Ben Birkenfeld1

  • 1RNA Mediated Gene Regulation Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA.

RNA Biology
|February 21, 2022
PubMed

Insights

Drosha enzyme cleavage of primary microRNAs (pri-miRNAs) creates mature microRNAs. Pri-miRNA structural flexibility and internal loops influence Drosha

Area of Science:

  • Molecular Biology
  • Genetics
  • Biochemistry

Background:

  • Drosha enzyme processing of primary microRNAs (pri-miRNAs) is critical for generating mature microRNAs (miRNAs).
  • Alternative Drosha cleavage sites lead to 5' isoforms (isomiRs) with distinct biological functions.
  • Understanding the structural determinants of Drosha cleavage fidelity is essential for miRNA biogenesis research.

Purpose of the Study:

  • To investigate how pri-miRNA structures influence Drosha cleavage fidelity.
  • To elucidate the mechanisms driving the production of 5' isomiRs.
  • To explore the role of RNA-binding proteins in modulating Drosha cleavage.

Main Methods:

  • Systematic in vitro and in vivo analysis of endogenous pri-miRNA maturation.
  • Structural analysis of pri-miRNAs, including internal loops and G·U wobble pairs.
  • Bioinformatic analysis of patient data from The Cancer Genome Atlas (TCGA).

Main Results:

  • Pri-miRNA structural flexibility significantly impacts Drosha cleavage fidelity.
  • Internal loops and G·U wobble pairs promote non-canonical Drosha cleavage, generating 5' isomiRs.
  • Alternative Drosha cleavage is a tunable process influenced by pri-miRNA-associated RNA-binding proteins, as evidenced by TCGA data.

Conclusions:

  • Altering pri-miRNA structure modulates Drosha cleavage fidelity.
  • Structural features like flexibility and internal loops are key determinants of 5' isomiR biogenesis.
  • This mechanism offers a potential explanation for 5' isomiR production in tumors.
Keywords:
5’ isomiRsDroshaRNA structureRNA-binding proteinsalternative cleavagecleavage fidelitydicerpri-miRNA

More Related Videos

Substrate Generation for Endonucleases of CRISPR/Cas Systems11:53

Substrate Generation for Endonucleases of CRISPR/Cas Systems

Published on: September 8, 2012

27.6K
Improving Small RNA-seq: Less Bias and Better Detection of 2'-O-Methyl RNAs08:49

Improving Small RNA-seq: Less Bias and Better Detection of 2'-O-Methyl RNAs

Published on: September 16, 2019

7.8K

Related Concept Videos

RNA Structure01:19

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form complex secondary and tertiary structures. Such structures play essential roles in the regulation of transcription and translation.
Different Types of RNA Have the Same Basic Structure
There are three main types of ribonucleic acid (RNA) involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). All three...
5.5K
Nucleic Acid Structure01:25

Nucleic Acid Structure

The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group on the ribose's second carbon and a hydrogen on the deoxyribose's second carbon. The phosphate residue attaches to the hydroxyl group of the 5′ carbon of one sugar and the hydroxyl group of the 3′ carbon of the sugar of the next nucleotide, which forms  a 5′ to 3′ phosphodiester linkage.
DNA Structure
DNA...
7.4K
piRNA - Piwi-interacting RNAs02:57

piRNA - Piwi-interacting RNAs

PIWI-interacting RNAs, or piRNAs, are the most abundant short non-coding RNAs. More than 20,000 genes have been found in humans that code for piRNAs while only 2000 genes have been found for miRNAs. piRNAs can act at the transcriptional and post-transcriptional levels and have a vital role in silencing transposable elements present in germ cells. They are also involved in epigenetic silencing and activation. Previously, they were thought to function only in germ cells but new evidence suggests...
7.1K
Pre-mRNA Processing: Modification of pre-mRNA Ends01:35

Pre-mRNA Processing: Modification of pre-mRNA Ends

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a cap to the 5' end of the growing transcript. In this process, a 5' phosphate is replaced by modified guanosine that has a methyl group attached (7-methyl guanosine). This 5' cap helps...
10.7K
pre-mRNA Processing02:01

pre-mRNA Processing

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or pre-mRNA to distinguish it from mature mRNA.
Once about 20-40 ribonucleotides have been joined together by RNA polymerase, a group of enzymes adds a “cap” to the 5’ end of the growing transcript. In this process, a 5’ phosphate is replaced by modified guanosine that has a methyl group attached to it (7-Methyl...
53.9K
Ribosomal RNA Synthesis02:53

Ribosomal RNA Synthesis

Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
13.6K