Tmem119-EGFP and Tmem119-CreERT2 Transgenic Mice for Labeling and Manipulating Microglia

Area of Science:

• Neuroscience
• Immunology
• Genetics

Background:

• Microglia, the brain's resident macrophages, play crucial roles in neurological health and disease.
• Existing genetic tools lack specificity, hindering precise study of microglia distinct from other brain macrophages.
• The microglia-specific gene Tmem119 presents a novel target for developing improved genetic research models.

Purpose of the Study:

• To generate and characterize novel knock-in mouse models for microglia identification and manipulation.
• To utilize the Tmem119 gene for creating specific transgenic tools for microglia research.
• To assess the specificity and efficacy of EGFP and CreERT2 expression in the new mouse lines.

Main Methods:

• Generation of knock-in mice using the Tmem119 gene to express EGFP or CreERT2.
• Genetic and qPCR analysis to confirm transgene positioning and endogenous Tmem119 expression.
• Immunofluorescence and flow cytometry to evaluate EGFP and CreERT2 specificity in microglia and other cell types.

Main Results:

• Tmem119-EGFP mice show complete and faithful labeling of parenchymal microglia, distinct from other brain macrophages.
• Tmem119-CreERT2 mice demonstrate CreERT2 activity primarily in microglia upon tamoxifen induction, with some leptomeningeal cell activity.
• Both lines exhibit minimal EGFP expression or CreERT2 activity in blood monocytes, confirming high specificity.

Conclusions:

• The novel Tmem119-EGFP and Tmem119-CreERT2 mouse models provide the most specific genetic tools to date for microglia research.
• These transgenic lines enable precise identification and manipulation of microglia within the brain's myeloid compartment.
• The developed tools significantly enhance the capacity for studying microglia function in various physiological and pathological contexts.