Aldh1a2 Conditional Knockout mouse models

Encoding RALDH2, Aldh1a2 is the mouse ortholog of human ALDH1A2 and the dominant source of embryonic all-trans retinoic acid, oxidizing retinaldehyde within paraxial and lateral plate mesoderm, epicardium, and meninges to establish the posterior-to-anterior retinoid gradient read by RAR and Hox targets. Loss of this single enzyme is not tolerated: germline nulls arrest around midgestation with unlooped heart tubes, absent forelimb buds, shortened trunks, and disrupted hindbrain segmentation, a lethality partially rescuable by maternal retinoic acid supplementation, so timed dietary rescue must be planned into any constitutive line. That embryonic requirement makes conditional floxed alleles the practical design for adult immunology, where dendritic cell and stromal RALDH2 drives gut homing and regulatory T cell induction. Paralogous Aldh1a1 and Aldh1a3 occupy largely nonoverlapping domains and do not rescue the early mesodermal deficit. Pair the flox with tissue-restricted Cre drivers such as Cd11c-Cre or Wt1-Cre when the endpoint is retinoid-dependent cell fate rather than gross morphogenesis.

Tissue restricted knockout of Aldh1a2 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.