RRC ID 73139
Author Durant-Vesga J, Suzuki N, Ochi H, Le Bouffant R, Eschstruth A, Ogino H, Umbhauer M, Riou JF.
Title Retinoic acid control of pax8 during renal specification of Xenopus pronephros involves hox and meis3.
Journal Dev Biol
Abstract Development of the Xenopus pronephros relies on renal precursors grouped at neurula stage into a specific region of dorso-lateral mesoderm called the kidney field. Formation of the kidney field at early neurula stage is dependent on retinoic (RA) signaling acting upstream of renal master transcriptional regulators such as pax8 or lhx1. Although lhx1 might be a direct target of RA-mediated transcriptional activation in the kidney field, how RA controls the emergence of the kidney field remains poorly understood. In order to better understand RA control of renal specification of the kidney field, we have performed a transcriptomic profiling of genes affected by RA disruption in lateral mesoderm explants isolated prior to the emergence of the kidney field and cultured at different time points until early neurula stage. Besides genes directly involved in pronephric development (pax8, lhx1, osr2, mecom), hox (hoxa1, a3, b3, b4, c5 and d1) and the hox co-factor meis3 appear as a prominent group of genes encoding transcription factors (TFs) downstream of RA. Supporting the idea of a role of meis3 in the kidney field, we have observed that meis3 depletion results in a severe inhibition of pax8 expression in the kidney field. Meis3 depletion only marginally affects expression of lhx1 and aldh1a2 suggesting that meis3 principally acts upstream of pax8. Further arguing for a role of meis3 and hox in the control of pax8, expression of a combination of meis3, hoxb4 and pbx1 in animal caps induces pax8 expression, but not that of lhx1. The same combination of TFs is also able to transactivate a previously identified pax8 enhancer, Pax8-CNS1. Mutagenesis of potential PBX-Hox binding motifs present in Pax8-CNS1 further allows to identify two of them that are necessary for transactivation. Finally, we have tested deletions of regulatory sequences in reporter assays with a previously characterized transgene encompassing 36.5 ​kb of the X. tropicalis pax8 gene that allows expression of a truncated pax8-GFP fusion protein recapitulating endogenous pax8 expression. This transgene includes three conserved pax8 enhancers, Pax8-CNS1, Pax8-CNS2 and Pax8-CNS3. Deletion of Pax8-CNS1 alone does not affect reporter expression, but deletion of a 3.5 ​kb region encompassing Pax8-CNS1 and Pax8-CNS2 results in a severe inhibition of reporter expression both in the otic placode and kidney field domains.
Volume 493
Pages 17-28
Published 2023-1-1
DOI 10.1016/j.ydbio.2022.10.009
PII S0012-1606(22)00199-3
PMID 36279927
MeSH Aldehyde Dehydrogenase 1 Family Animals Gene Expression Regulation, Developmental Kidney / metabolism Paired Box Transcription Factors / genetics Paired Box Transcription Factors / metabolism Pronephros* / metabolism Retinal Dehydrogenase / metabolism Tretinoin* / metabolism Tretinoin* / pharmacology Xenopus Proteins / genetics Xenopus Proteins / metabolism Xenopus laevis / genetics Xenopus laevis / metabolism
IF 2.896
Clawed frogs / Newts Xenopus tropicalis