# Damaged RNA as a mediator of alkylation responses

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2020 · $373,766

## Abstract

Project Summary: The objective of this proposal is to define the role of damaged RNA in mediating
signaling events during cancer chemotherapy. In the previous funding cycle of this grant, we uncovered a novel
ubiquitin-dependent signaling pathway initiated specifically when cells encounter alkylating agents, one of the
most commonly used systemic modalities for cancer treatment. This pathway depends on the RNF113A E3
ubiquitin ligase, which in turn recruits the ASCC DNA helicase complex as well as the ALKBH3
demethylase/dealkylase. To date, most of the studies on alkylation damage, including our own work, has focused
on how alkylated lesions are recognized and repaired on DNA. Yet, damage to RNA is far more abundant than
damaged DNA in any cell which encounters an alkylating agent. Using novel tools to induce or repair alkylated
RNA, we have found that alkylated RNA is necessary and sufficient to activate the E3 ligase function of RNF113A
and recruit the ASCC complex. Our evidence also indicates that RNF113A is a phospho-activated E3 ligase,
and that the CDK12 kinase is responsible for its phosphorylation. This data serves as the basis for our model
that RNA alkylation functions upstream of a kinase (CDK12) that activates an E3 ligase (RNF113A), which in
turn recruits an alkylation repair complex (ASCC-ALKBH3). In this proposal, we will seek to understand the
mechanistic basis for how RNA alkylation recapitulates the activation of the RNF113A-ASCC-ALKBH3 pathway
(Aim 1). We will characterize the role of this pathway in removing damaged RNAs, preventing replication-
transcription conflicts and RNA-DNA hybrids (R-loops) (Aim 2). Finally, we will determine the functional
consequences of CDK12-mediated phosphorylation in the activation of RNF113A and its role in tumor
chemotherapy responses (Aim 3). Notably, since small molecule CDK12 inhibitors are already available, we will
be able to test whether targeting this pathway will improve alkylation therapy responses. Together, our work will
establish a new paradigm in nucleic acid damage signaling, where RNA damage plays a central role in mediating
DNA repair.

## Key facts

- **NIH application ID:** 9974085
- **Project number:** 2R01CA193318-06
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Nima Mosammaparast
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $373,766
- **Award type:** 2
- **Project period:** 2015-04-01 → 2025-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9974085

## Citation

> US National Institutes of Health, RePORTER application 9974085, Damaged RNA as a mediator of alkylation responses (2R01CA193318-06). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9974085. Licensed CC0.

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