The nephron, functional unit of the vertebrate kidney, is specialized in metabolic wastes excretion and body fluids osmoregulation. Given the high evolutionary conservation of gene expression and segmentation patterning between mammalian and amphibian nephrons, the Xenopus laevis pronephric kidney offers a simplified model for studying nephrogenesis. The Lhx1 transcription factor plays several roles during embryogenesis, regulating target genes expression by forming multiprotein complexes with LIM binding protein 1 (Ldb1). However, few Lhx1-Ldb1 cofactors have been identified for kidney organogenesis. By tandem- affinity purification from kidney-induced Xenopus animal caps, we identified single-stranded DNA binding protein 2 (Ssbp2) interacts with the Ldb1–Lhx1 complex. Ssbp2 is expressed in the Xenopus pronephros, and knockdown prevents normal morphogenesis and differentiation of the glomus and the convoluted renal tubules. We demonstrate a role for a member of the Ssbp family in kidney organogenesis and provide evidence of a fundamental function for the Ldb1–Lhx1-Ssbp transcriptional complexes in embryonic development.

肾单位是脊椎动物肾脏的功能单位，专门负责代谢废物的排泄和体液渗透压调节。鉴于哺乳动物和两栖动物肾单位之间基因表达和分割模式的高度进化保守性，非洲爪蟾原肾为研究肾发生提供了一个简化的模型。 Lhx1 转录因子在胚胎发生过程中发挥多种作用，通过与 LIM 结合蛋白 1 (Ldb1) 形成多蛋白复合物来调节靶基因表达。然而，很少有 Lhx1-Ldb1 辅助因子被发现与肾脏器官发生有关。通过对肾诱导的非洲爪蟾动物帽进行串联亲和纯化，我们鉴定出单链 DNA 结合蛋白 2 (Ssbp2) 与 Ldb1-Lhx1 复合物相互作用。 Ssbp2在非洲爪蟾中表达，敲低会阻止肾小球和肾小管的正常形态发生和分化。我们证明了 Ssbp 家族成员在肾脏器官发生中的作用，并提供了 Ldb1-Lhx1-Ssbp 转录复合物在胚胎发育中基本功能的证据。