Kcnj2 Conditional Knockout mouse models

Kcnj2, the mouse ortholog of human KCNJ2, encodes Kir2.1, the dominant subunit of the strong inward rectifier current IK1 that stabilizes the resting membrane potential of cardiac myocytes, skeletal muscle, and many neurons, and that contributes the terminal phase of cardiac repolarization. Rectification is not intrinsic gating but voltage-dependent block by intracellular magnesium and polyamines at Asp172 and cytoplasmic pore residues, and channel opening requires PIP2, with a Golgi export motif and a PDZ-binding tail controlling trafficking. Loss-of-function and dominant-negative KCNJ2 mutations cause Andersen-Tawil syndrome with periodic paralysis, prolonged QT, and dysmorphic features, whereas gain-of-function alleles cause short QT syndrome type 3, so the design fork is between disease knockin and conditional null. Nulls die neonatally with cleft palate, making cardiac or neuron-restricted conditional deletion necessary for adult work. Kir2.2 and Kir2.3 encoded by Kcnj12 and Kcnj4 heteromerize and blunt single-locus loss, so plan compound genetics for full IK1 collapse.

Conditional deletion of Kcnj2 limits the genetic change to the lineage you choose. That helps in oncology, immunology, and metabolic work where systemic loss would muddy the read. After you confirm Cre specificity, crossing to Kcnj2 floxed stock yields usable cohorts.