Cell-type-specific labeling of endogenous proteins using the split GFP system in Drosophila

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Accurate identification of endogenous protein localization is vital for understanding cellular functions.
• In vivo cell-type-specific protein labeling has been a significant challenge.
• The self-complementing split green fluorescent protein (GFP_1-10/11) system offers a potential solution.

Purpose of the Study:

• To present a detailed protocol for cell-type-specific endogenous protein labeling in fruit flies using the GFP_1-10/11 system.
• To demonstrate the application of this system for visualizing protein localization in vivo.
• To validate the technique using the teneurin-m (Ten-m) gene as a model.

Main Methods:

• Utilized the GFP_1-10/11 system for protein labeling.
• Inserted the GFP₁₁ fragment into a specific genomic locus (Ten-m) via Minos-mediated integration cassette (MiMIC) insertion.
• Expressed the GFP_1-10 fragment using a Gal4 driver line for cell-specific fluorescence reconstitution.

Main Results:

• Successfully generated and validated GFP₁₁ protein trap lines for the Ten-m gene.
• Achieved precise, cell-type-specific labeling of endogenous Ten-m proteins in fruit fly larval brains.
• Demonstrated that neither GFP_1-10 nor GFP₁₁ alone produces fluorescence, ensuring specific signal detection.

Conclusions:

• The GFP_1-10/11 system provides a robust method for cell-type-specific endogenous protein localization in fruit flies.
• This technique significantly improves the ability to image protein localization patterns in vivo.
• The method is adaptable to other model organisms, broadening its applicability in biological research.