# Structural and Functional Analysis of Human DICER1

> **NIH NIH F31** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2021 · $38,104

## Abstract

PROPOSAL SUMMARY/ABSTRACT
 DICER1 is a multidomain protein that contains two RNase III domains (RNase IIIa and IIIb) that catalyze the
final cleavage of a pre-microRNA to form the 3p (3' prime end) and 5p (5' prime end) strands of a mature
microRNA (miRNA), respectively. While some initial characterization has been done to show how DICER1 binds
to a pre-miRNA substrate, the exact mechanism by which the RNase III domains interact with the pre-miRNA
during pre-miRNA cleavage is still largely unclear. One of the major causes behind this gap in knowledge is that
no high-resolution (sub-3.5Å) structures of DICER1 are available for building a molecular model detailing how
the protein engages and processes pre-miRNA substrates.
 Recent biochemical studies have shown that point mutations at key metal-binding residues in the RNase IIIb
domain, which are common in many DICER1 Syndrome patients, cause defective miRNA processing. thus,
these mutations offer a unique strategy to structurally understand how pre-miRNAs binds to the RNase III
domains without interference of the full cleavage reaction. Additionally, recent work from the Garner lab has led
to the discovery of distinct classes of natural products that can be used to inhibit DICER1-mediated pre-miRNA
maturation. Thus, these newly discovered compounds can also be used as chemical tools to modulate DICER1
activity, and as an additional strategy by which to structurally and functionally characterize DICER1 interactions
with a pre-miRNA.
 This research proposal aims to characterize the structure-function relationship of human DICER1 bound to
pre-miRNA substrates during miRNA biogenesis. The specific objective of this proposal is to determine how
alterations due to mutations in the RNase III domains can be used to lock DICER1 in different conformational
states, as well as to utilize natural products to modulate pre-miRNA interactions. This work is based on the
hypothesis that DICER1 must undergo key conformational changes in the RNase III domains during miRNA
cleavage in order to properly orient the pre-miRNA substrate towards a favorable interaction with the critical
metal binding residues found in the catalytic active site.
 To evaluate my hypothesis, I will combine cryo-EM structural studies as well as pre-miRNA cleavage and
binding assays to study the underlying mechanism that dictates miRNA biogenesis. Furthermore, this work will
shed new light on key binding pockets within DICER1 that can be targeted using small molecules and natural
products as an alternative approach to therapeutically treating miRNA linked diseases.

## Key facts

- **NIH application ID:** 10219810
- **Project number:** 5F31GM139291-02
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Rachel Torrez
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $38,104
- **Award type:** 5
- **Project period:** 2020-09-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10219810

## Citation

> US National Institutes of Health, RePORTER application 10219810, Structural and Functional Analysis of Human DICER1 (5F31GM139291-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10219810. Licensed CC0.

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