Sdhb Knockout mouse models

Sdhb, the mouse ortholog of human SDHB, encodes the iron-sulfur subunit of complex II, carrying the [2Fe-2S], [4Fe-4S] and [3Fe-4S] clusters that form the electron relay from the FAD of SDHA to the ubiquinone site created by SDHC and SDHD. Germline loss-of-function alleles combined with somatic loss of the wild-type copy define one of the strongest tumor suppressor mechanisms in paraganglioma, pheochromocytoma, gastrointestinal stromal tumor and renal cell carcinoma, and carriers show a notably high rate of metastatic disease. The mechanism is metabolite driven: accumulated succinate competitively inhibits alpha-ketoglutarate-dependent dioxygenases including TET demethylases, KDM histone demethylases and PHD prolyl hydroxylases, producing a hypermethylator phenotype and pseudohypoxic HIF stabilization. Conditional nulls in chromaffin or neural crest lineages are therefore the tumor-relevant design, while knockins model hypomorphic bioenergetic disease. No paralog substitutes. Match the allele to methylome, HIF target or tumor latency endpoints and validate lineage-specific Cre expression.

Whole body loss of Sdhb gives the clearest readout when the question is whether the gene is required at all. Follow up tissue work can still move to a conditional allele if lethality or compensation appears.