Bax Conditional Knockout mouse models

Mouse Bax, ortholog of human BAX, encodes the cytosolic counterpart to BAK and executes mitochondrial outer membrane permeabilization once activated by upstream ligands. In healthy cells BAX cycles between cytosol and mitochondria, its alpha9 helix sequestered in its own hydrophobic groove and continuously retrotranslocated by BCL2L1 and MCL1, so commitment requires BH3-only activators (BID, BIM, PUMA) to engage either the canonical groove or the alpha1 to alpha6 rear site, driving conformational opening, membrane insertion, symmetric BH3-in-groove dimers, and pore formation upstream of APAF1 apoptosome assembly. Since BAK1 is largely redundant, informative genetics almost always requires compound alleles, and germline Bax Bak1 double nulls are frequently perinatal lethal with retained interdigital webs and expanded neural progenitors. Conditional Bax flox stocks paired with Bak1 flox and a lineage-restricted Cre are therefore the practical route, with non-functional point knockins reserved for questions about oligomerization mechanism rather than absolute apoptotic capacity.

Tissue restricted knockout of Bax 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.