Gabrg2 Knockout mouse models

Gabrg2 encodes the γ2 subunit, ortholog of human GABRG2, present in the large majority of synaptic GABA-A receptors, where it completes the α1β2γ2 pentamer, forms the complementary face of the benzodiazepine binding site with α, and is strictly required for clustering at inhibitory postsynaptic sites through gephyrin, collybistin and neuroligin-2 interactions. Human dominant variants map cleanly to mechanism: R43Q in the benzodiazepine site causes febrile seizures and childhood absence epilepsy by impairing trafficking, K289M in the extracellular M2 to M3 loop causes generalized epilepsy with febrile seizures plus by accelerating deactivation, and truncations cause Dravet-like encephalopathy through dominant negative retention. Constitutive nulls die within the first postnatal days with loss of synaptic receptor clustering, so a conditional null with Camk2a-Cre or an interneuron driver is required for adult circuit work, while patient knockins reproduce specific seizure phenotypes. No other γ isoform substitutes appreciably in forebrain synapses.

Global Gabrg2 deletion answers broad mechanism questions quickly. If timing or site matters, conditional alleles are a natural next step after the null is characterized.