Cacna1d Knockin mouse models

Cacna1d, ortholog of human CACNA1D, encodes CaV1.3, an L-type α1D channel distinguished from CaV1.2 by activation at markedly more negative potentials and by weak dihydropyridine sensitivity, properties that make it the pacemaking current in sinoatrial and adrenal chromaffin cells and the sole channel gating tonic glutamate release at cochlear inner hair cell ribbon synapses. Extensive C-terminal alternative splicing and a modulatory C-terminal domain tune calcium-dependent inactivation, and human alleles split cleanly by direction: recessive loss of function produces sinoatrial node dysfunction with deafness, whereas somatic and germline gain-of-function substitutions such as A749G cause aldosterone-producing adenomas and primary aldosteronism with seizures and neurologic disability. Constitutive nulls are viable but deaf and bradycardic, giving a tractable model, while a gain-of-function knockin isolates the aldosterone and neurodevelopmental arm. CaV1.2 compensates in several tissues, so quantify Cacna1c transcript and current before attributing residual L-type conductance.

Cacna1d knockin models place a defined sequence at the endogenous locus. Expression stays under native regulation, which matters for reporters, tags, and precise allele swaps.