Notch3 Conditional Knockout mouse models

Notch3, the mouse ortholog of human NOTCH3, encodes a receptor with a shorter extracellular region than Notch1 and expression concentrated in vascular smooth muscle and pericytes, where canonical Adam10 and gamma-secretase processing releases an intracellular domain that acts through Rbpj and Maml to drive Heyl and mural cell maturation. Its disease logic is distinctive and not simple loss of function: CADASIL arises from cysteine-altering substitutions within EGF repeats that promote ectodomain multimerization and granular osmiophilic material deposition in arteriolar walls, a proteinopathy mechanism, whereas PEST-truncating alleles that stabilize signaling cause lateral meningocele syndrome. Homozygous nulls are viable with immature, poorly differentiated arterial smooth muscle and impaired myogenic responses, so germline alleles are usable, but the informative CADASIL model requires a patient-matched cysteine substitution knockin, ideally in a humanized EGF repeat context, rather than deletion. Notch1 contributes to mural cell biology, so compound alleles and a smooth muscle driver refine interpretation.

Tissue restricted knockout of Notch3 keeps wild type function everywhere else. Breeding is often more robust, and the setup mirrors patient biology where mutations arise in a subset of cells.