# Rapid Fluorescent Tagging of Endogenous Proteins in Mouse Models

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA BERKELEY · 2020 · $196,250

## Abstract

Project summary
Genetically engineered mouse models are an indispensable tool for studying human
development and disease, enabling us to characterize gene functions in vivo, to investigate the
cellular and molecular mechanisms of physiological and pathological processes, and to establish
faithful disease models for drug screen. To date, most mouse models are engineered to
recapitulate human disease phenotype, yet more sophisticated mouse models are in demand to
study disease gene function in a native cellular background, to perform single cell based
analyses and to set up high-throughput reporter-based screens for phenotypes or therapy.
Fluorescent tagging of endogenous genes is a particularly powerful strategy, allowing the
characterization of subcellular localization of proteins, identification of interaction partners, and
isolation of specific cell populations in the context of development and disease. Engineering
functional tags in an endogenous gene locus of interest preserves endogenous expression and
minimizing genomic disruption, but the technology still remains inefficient, costly and laborious.
We recently developed CRISRP-EZ (CRISPR RNP Electroporation of Zygotes), an
electroporation-based technology that outperforms microinjection in efficiency, simplicity, cost,
and throughput for mouse genome editing. Based on the CRISPR-EZ technology, we aim to
develop novel technologies to achieve rapid fluorescent tagging of endogenous proteins with
unprecedented efficiency, simplicity, throughput and cost saving. First, we will employ the self-
complementing split-GFP system to achieve functional GFP tagging of endogenous genes in
vivo using CRISPR-EZ. Second, we will develop CRISPR-READI (CRISPR RNP
Electroporation and AAV Donor Infection) to engineer full length fluorescent protein tagging on
endogenous loci in mice by AAV-mediated HDR editing. Taken together, our technologies will
allow efficient and high throughput fluorescent tagging in mouse disease models for
comprehensive mechanistic studies and powerful drug screening.

## Key facts

- **NIH application ID:** 9993600
- **Project number:** 5R21OD027053-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA BERKELEY
- **Principal Investigator:** Lin He
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $196,250
- **Award type:** 5
- **Project period:** 2019-08-15 → 2022-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9993600

## Citation

> US National Institutes of Health, RePORTER application 9993600, Rapid Fluorescent Tagging of Endogenous Proteins in Mouse Models (5R21OD027053-02). Retrieved via AI Analytics 2026-06-05 from https://api.ai-analytics.org/grant/nih/9993600. Licensed CC0.

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