XB-ART-164Development 2006 Aug 01;13315:2961-71. doi: 10.1242/dev.02458.
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The Notch-effector HRT1 gene plays a role in glomerular development and patterning of the Xenopus pronephros anlagen.
Notch signaling has been shown to play a role in cell fate decisions in the Xenopus pronephros anlagen. Here, we show that the Xenopus Hairy-related transcription factor (HRT) gene XHRT1, and the Hairy/Enhancer of split (HES) genes Xhairy1, Xhairy2b, esr9 and esr10, have distinct restricted dynamic expression patterns during pronephros development, and that their expression is regulated by Notch. XHRT1, which is the earliest and strongest gene expressed in the pronephric region, is initially transcribed predominantly in the forming glomus, where it is downregulated by antisense morpholino oligonucleotide inhibition of xWT1. Later, it is activated in the most dorsoanterior part of the pronephros anlagen that gives rise to the proximal tubules. In agreement with this dynamic expression profile, we found that early activation of Notch favors glomus, whereas only later activation promotes proximal tubule formation. We show that, among the bHLH-O factors tested, only XHRT1 efficiently inhibits distal tubule and duct formation, and that only its translational inhibition causes a reduction of the expression of proximal tubule and glomus markers. Using domain swap experiments, we found that the XHRT1 C-terminal region is crucial for its activity. Together, our results provide evidence that XHRT1 plays an important role in glomerular development and early proximodistal patterning that is distinct from those of the other pronephric bHLH repressors.
PubMed ID: 16818449
Article link: Development
Species referenced: Xenopus
Genes referenced: dll1 gal.2 hes1 hes4 hes5.5 hes5.6 hes5.7 hey1 jag1 mecom mmut notch1 nphs1 pax8 pdzk1 rgn wt1
Morpholinos: hes4 MO1 hes4 MO2 hes5.5 MO1 hes5.7 MO2 hey1 MO2 wt1 MO2 wt1 MO3
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