# Rapid production and dissemination of intersectional genetic alleles for the study of nervous system circuit development and function in the mouse.

> **NIH NIH R21** · BAYLOR COLLEGE OF MEDICINE · 2020 · $237,750

## Abstract

Project Summary
The goal of this project is to build and distribute a community library of more than 100 mouse intersectional genetic
alleles to facilitate the developmental, anatomical, molecular, and functional characterization of neural circuit organization
in behavior and physiology. Even within narrowly defined cell types, significant diversity is found at multiple levels
including genetic and molecular signatures, activity patterns, and synaptic connectivity. Current challenges now center
on tools to identify, access, and study cell populations with increasing precision. Intersectional genetics offers
exceptionally high resolution to consistently delineate distinct cell types in the embryo and adult mouse for functional,
molecular and anatomical studies. Intersection genetics utilizes a ubiquitously expressed conditional allele that is
activated by Cre and Flp site specific recombinases. Upon activation, the intersectional genetic alleles may express any
number of Genetically Encodable Effector Molecules (GEEMS), such as channelrhodopsins for neural activity
perturbations or an L10-GFP ribotrap fusion to affinity purify translating mRNAs. The intersectional allele is activated by
overlapping expression of both Flp and Cre recombinases in the same cell. Traditionally, these recombinases have been
deployed as gene knock-in or transgenic alleles that are designed to express in a cell or gene specific fashion. The use
of two selectors (Cre and Flp) to define a cellular population enables high specificity and modularity in combining any set
of Cre, Flp and intersectional alleles to fit an experiment. The number of Cre and Flp recombinase mouse lines are
constantly growing, giving greater access to increasing numbers of cell types. Additionally, these recombinases are the
focus of multiple efforts to deploy them in ways that select cells based on other unique properties such as neuronal
activity and synaptic connectivity. Despite the modularity and advantages offered by intersectional genetic mouse tools,
their use remains limited due to the small number of publically available intersectional responsive alleles that express
unique GEEMS and the difficulty in producing new intersectional mouse lines. Toward increasing the number of
intersectional lines available to the mouse community, we propose a production pipeline in the following three aims
create a suite of resources for anyone to easily make their own intersectional mouse line, to produce over 100 targeted
ES cell lines that can be developed into mouse lines, as well as 10-15 high demand mouse lines. Aim 1) Assemble
community input and generate a facile pipeline for the rapid production of intersectional targeting vectors. Our
lab has engineered several different intersectional genetic targeting cassettes to quickly build new alleles based on public
input and rapidly integrate new effector molecules. Aim 2) Use multiplex gene targeting for cost-efficient production
of a large library of int...

## Key facts

- **NIH application ID:** 9842634
- **Project number:** 5R21OD025327-02
- **Recipient organization:** BAYLOR COLLEGE OF MEDICINE
- **Principal Investigator:** Russell S Ray
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $237,750
- **Award type:** 5
- **Project period:** 2019-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9842634

## Citation

> US National Institutes of Health, RePORTER application 9842634, Rapid production and dissemination of intersectional genetic alleles for the study of nervous system circuit development and function in the mouse. (5R21OD025327-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9842634. Licensed CC0.

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