# Generation of Cre/lox rats

> **NIH NIH R24** · UNIVERSITY OF SOUTHERN CALIFORNIA · 2020 · $703,637

## Abstract

ABSTRACT
This R24 resource proposal seeks to promote broad and cost-effective usage of rat models through generation
and distribution of a panel of popular Cre/lox knockin rats. Rats have long been used as models that better
replicate human physiology and pathophysiology than do mice and are the preferred model for the study of
many human diseases. Use of rats to model human disease, however, has been limited until recently by the
inability to generate germline-competent rat embryonic stem (ES) cells, precluding the use of ES-cell based
approaches to produce conditional/inducible knockout rats. In 2010, we generated the first gene knockout rats
by homologous recombination-based gene targeting in ES cells. More recently, we have generated a panel of
genetically modified rat lines including gene knockout, knockin of point mutation, knockin of reporters, Cre
drivers, and floxed rats. A major strength of the ES cell approach is the ability, in conjunction with Cre/lox
technology, to generate rats in which genes are inactivated at specific times and/or in specific tissues or
organs. We have assembled a strong group of investigators with complementary expertise to develop a panel
of universal Cre/lox reporter rats (Aim 1), cell-specific and inducible Cre rats (Aim 2), and floxed rats in which
specific genes of interest are flanked by loxP sites (Aim 3). These Cre/lox rats will allow investigators to
visualize specific cell types in situ and can also serve as the basis for the generation of conditional/inducible
knockout rats. Cre/lox rats generated in this project will be distributed through the Missouri Rat Resource and
Research Center (RRRC) (Aim 4). Availability of these rats would combine the significant biological
advantages of the rat with the genetic tractability of the mouse, providing investigators with a highly relevant in
vivo model with which to study the contributions of specific genes and pathways to pathogenesis of a number
of important human diseases.

## Key facts

- **NIH application ID:** 9924679
- **Project number:** 5R24OD024626-04
- **Recipient organization:** UNIVERSITY OF SOUTHERN CALIFORNIA
- **Principal Investigator:** Qilong Ying
- **Activity code:** R24 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $703,637
- **Award type:** 5
- **Project period:** 2017-08-15 → 2022-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9924679

## Citation

> US National Institutes of Health, RePORTER application 9924679, Generation of Cre/lox rats (5R24OD024626-04). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9924679. Licensed CC0.

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