title: Prox1 is a novel coregulator of Ff1b and is involved in the embryonic development of the zebra fish interrenal primordium.
abstract: Steroidogenic factor 1 (SF-1) plays an essential role in adrenal development, although the exact molecular mechanisms are unclear. Our previous work established that Ff1b is the zebra fish homologue of SF-1 and that its disruption by antisense morpholinos leads to a complete ablation of the interrenal organ. In this study, results of biochemical analyses suggest that Ff1b and other Ff1 members interact with Prox1, a homeodomain protein. Fine mapping using site-directed mutants showed that this interaction requires an intact Ff1b heptad 9 and AF2, as well as Prox1 NR Box I. In vivo, this physical interaction led to the inhibition of Ff1-mediated transactivation of pLuc3XFRE, indicating that Prox1 acts to repress the transcriptional activity of Ff1b. In situ hybridization demonstrates that prox1 colocalizes with ff1a and ff1b in the liver and interrenal primordia, respectively. Embryos microinjected with prox1 morpholino displayed a consistent partial reduction of 3 eta-Hsd activity in the interrenal organ, while ff1b morpholino led to a disappearance of prox1. Based on these results, we propose that during the course of interrenal organogenesis, Prox1 functions as a tissue-specific coregulator of Ff1b and that the subsequent inhibition of Ff1b activity, after its initial roles in the specification of interrenal primordium, is critical for the maturation of the interrenal organ.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins / Q000378:metabolism / Q000502:physiology*; D017403:In Situ Hybridization; D007668:Kidney / Q000196:embryology*; D008099:Liver / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D025521:Tumor Suppressor Proteins; D020798:Two-Hybrid System Techniques; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000378:metabolism*; D001616:beta-Galactosidase / Q000378:metabolism; D000098551:Prospero-Related Homeobox 1 Protein
chemical_list: D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; C515056:NR5A2 protein, zebrafish; D020033:Protein Isoforms; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D029961:Zebrafish Proteins; C478921:nr5a1a protein, zebrafish; D000098551:Prospero-Related Homeobox 1 Protein; D001616:beta-Galactosidase