# Development of new methods for drug-inducible control of gene expression in model organisms

> **NIH NIH R01** · SCRIPPS RESEARCH INSTITUTE, THE · 2020 · $431,202

## Abstract

Abstract.
Biomedical research tremendously benefits from approaches that enable pharmacological control of gene
expression in live laboratory animals. However, current techniques have limitations that often imped the design
of transformative experimental paradigms. These include suboptimal temporal dynamics and undesired side
effects of inducing drugs on animal physiology and behavior. Our preliminary studies demonstrate that these
obstacles can be overcome with new approaches permitting acute regulation of nuclear protein function with
the antibiotic, trimethoprim (TMP). This innovative strategy takes advantage of destabilizing domains (DD) that
mediate instant degradation of synthesized proteins of interest (POI). TMP restores the stability of DD-POIs by
binding to DD tags with high affinity. When compared to other chemical-genetic methods, TMP-inducible
stabilization has several advantages: (i) TMP is an inexpensive commercially available small molecule that
efficiently penetrates peripheral tissues and the blood-brain barrier; (ii) TMP does not produce adverse effects
in mammals due to lack of endogenous targets; (iii) DDs can be fused to virtually any protein of interest; and
(iv) TMP stabilizes translated proteins with rapid time-course that does not depend on rates of mRNA
synthesis. We therefore hypothesize that expression of genetically encoded DD-POIs in model organisms will
facilitate a broad spectrum of studies that have not been previously feasible for technical reasons. Here we will:
1) Develop a versatile toolbox for TMP-inducible recombination of chromosomal and episomal DNA with
destabilized Cre recombinase (DD-Cre). This method can be used with numerous mouse lines carrying loxP-
flanked alleles, and to drive tissue-specific expression of genes of interest with recombinant viruses;
2) Leverage TMP-inducible stabilization of site-specific transcriptional repressors (DD-TR) for acute silencing
of multiple genes that act in the same pathway, a task that cannot be performed with other methods.
Our qualified interdisciplinary team will rely on mouse models to validate these tools in vivo. We will express
DD-Cre and DD-TRs in the brain to systematically characterize their sensitivity to TMP, kinetics of stabilization,
and activity on substrates. Moreover, we will exploit these novel systems in proof-of-principle neurobehavioral
experiments to investigate the mechanisms of learning and memory.

## Key facts

- **NIH application ID:** 9850266
- **Project number:** 5R01GM117049-04
- **Recipient organization:** SCRIPPS RESEARCH INSTITUTE, THE
- **Principal Investigator:** Anton Maximov
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $431,202
- **Award type:** 5
- **Project period:** 2017-04-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9850266

## Citation

> US National Institutes of Health, RePORTER application 9850266, Development of new methods for drug-inducible control of gene expression in model organisms (5R01GM117049-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9850266. Licensed CC0.

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