Generation and Characterization of a Cell Type-Specific, Inducible Cre-Driver Line to Study Olfactory Processing

Area of Science:

• Neuroscience
• Olfactory System Research
• Genetics and Molecular Biology

Background:

• The mammalian olfactory bulb processes complex sensory information via distinct cell types, including mitral cells (MCs) and tufted cells (TCs).
• Existing genetic tools lack the specificity to differentiate between MCs and TCs, hindering cell-type-specific investigations.
• Understanding MC and TC contributions is crucial for deciphering parallel processing in olfaction.

Purpose of the Study:

• To identify genes differentially expressed between mouse MCs and TCs.
• To generate a cell type-specific Cre-driver line for MCs.
• To provide a novel tool for studying MC-specific functions in olfactory processing.

Main Methods:

• Transcriptome analysis of a public single-cell RNA-seq dataset (Zeisel et al., 2018) to identify differentially expressed genes.
• In situ hybridization (ISH) validation of candidate genes.
• CRISPR/Cas9-mediated gene editing to create Cre-driver lines, specifically targeting the Lbhd2 gene.

Main Results:

• Identification of several differentially expressed genes, with Pkib and Lbdh2 emerging as promising candidates.
• Generation of an inducible Cre-driver line, Lbhd2-CreERT2.
• Demonstration that Lbhd2-CreERT2 allows tamoxifen-inducible, dose-dependent genetic labeling of MCs in mice, confirmed by location, projections, and in vivo responses.

Conclusions:

• The Lbhd2-CreERT2 mouse line is a valuable tool for specific genetic manipulation and labeling of mitral cells.
• This tool facilitates the investigation of cell type-specific roles in olfactory processing.
• The study highlights the utility of public datasets and gene editing in accelerating neuroscience research.