PGC-1α Expression Analysis During PV+ Interneuron Development Protocol
Phase 1: Mouse Breeding and Genotyping (Days 1-14)
Breeding Strategy: Cross PGC-1α flox/flox (B6;129-Ppargc1a<tm1.1Dlb>/J, JAX #024119) with PV-Cre driver line (B6;129P2-Pvalb<tm1(cre)Jpb>/J, JAX #017493) to generate PV-Cre;PGC-1α flox/flox conditional knockout (cKO) and Cre-negative PGC-1α flox/flox controls. Genotype via PCR (primer sets for Cre, flox, WT alleles).
Timed Pregnancy Setup: Set up overnight timed matings (vaginal plug = E0.5). Harvest embryos at E14.5, E17.5, P0, P7, P14, and P21 (n≥4 per genotype per timepoint). Genotype and sex-label all specimens.
...PGC-1α Expression Analysis During PV+ Interneuron Development Protocol
Phase 1: Mouse Breeding and Genotyping (Days 1-14)
Breeding Strategy: Cross PGC-1α flox/flox (B6;129-Ppargc1a<tm1.1Dlb>/J, JAX #024119) with PV-Cre driver line (B6;129P2-Pvalb<tm1(cre)Jpb>/J, JAX #017493) to generate PV-Cre;PGC-1α flox/flox conditional knockout (cKO) and Cre-negative PGC-1α flox/flox controls. Genotype via PCR (primer sets for Cre, flox, WT alleles).
Timed Pregnancy Setup: Set up overnight timed matings (vaginal plug = E0.5). Harvest embryos at E14.5, E17.5, P0, P7, P14, and P21 (n≥4 per genotype per timepoint). Genotype and sex-label all specimens.
Tissue Processing: Dissect cerebral cortex, fix in 4% PFA (24 hours, 4°C), cryoprotect in 30% sucrose, and embed in OCT. Cut coronal sections (20 μm) on a cryostat. Mount every 6th section for systematic sampling.
Phase 2: Immunohistochemical Staining (Days 15-21)
Multi-plex Staining: Perform immunohistochemistry on brain sections using Opal 4-color fluorescence kit (PerkinElmer). Stain sequence: PV (1:1000, Swant #P308), PGC-1α (1:200, Abcam #ab191695), Ki67 (proliferation marker, 1:200, Abcam #ab15580), and DAPI nuclear counterstain. Include no-primary and no-secondary controls for each run.
Image Acquisition: Image on Vectra 3.0 automated fluorescence microscope (20× objective) at 5 pre-frontal cortical fields per section (n=3 sections per animal). Acquire at consistent exposure settings for each channel across all samples.
Phase 3: Quantification and Spatial Analysis (Days 22-35)
Cell Counting: Use HALO software (Indica Labs) for automated cell detection and classification. Define PV+ cells as PV fluorescence > 3× background threshold. Quantify PGC-1α+ cells as percentage of PV+ population at each developmental stage. Count Ki67+PV+ double-positive cells to assess proliferation rates.
Developmental Trajectory Analysis: Plot PGC-1α expression frequency in PV+ interneurons from E14.5 to P21 for both cKO and control genotypes. Fit polynomial or logistic growth curves to characterize expression trajectory parameters (peak timing, plateau level).
Statistical Analysis: Compare cKO vs. control at each timepoint via two-way ANOVA (genotype × age) with Bonferroni post-hoc correction. Primary outcome: area under the PGC-1α+ developmental curve.