A dual requirement for Iroquois genes during Xenopus kidney development.
The Iroquois (Irx) genes encode evolutionary conserved homeoproteins. We report that Xenopus genes Irx1 and Irx3 are expressed and required during different stages of Xenopus pronephros development. They are initially expressed during mid-neurulation in domains extending over most of the prospective pronephric territory. Expression onset takes place after kidney anlage specification, but before pronephric organogenesis occurs. Later, during nephron segmentation, expression becomes restricted to the intermediate tubule region of the proximal-distal axis. Loss- and gain-of-function analyses, performed with specific morpholinos and inducible wild-type and dominant-negative constructs, reveal a dual requirement for Irx1 and Irx3 during pronephros development. During neurula stages, these genes maintain the specification of the pronephric territory and define its size. This seems to occur, at least in part, through positive regulation of Bmp signalling. Subsequently, Irx genes are required for proper formation of the intermediate tubule. Finally, we find that retinoic acid signalling activates both Irx1 and Irx3 genes in the pronephros.
Alarcón
Pilar
P
Centro Andaluz de Biología del Desarrollo, CSIC/UPO, Sevilla, Spain.
Rodríguez-Seguel
Elisa
E
Fernández-González
Ana
A
Rubio
Ruth
R
Gómez-Skarmeta
José Luis
JL
D000818:Animals; D001483:Base Sequence; D019521:Body Patterning / Q000187:drug effects / Q000235:genetics; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D005801:Genes, Homeobox / Q000187:drug effects; D018398:Homeodomain Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D007668:Kidney / Q000196:embryology* / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics; D014212:Tretinoin / Q000494:pharmacology; D029867:Xenopus Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism
D019485:Bone Morphogenetic Proteins; D017931:DNA Primers; D018398:Homeodomain Proteins; C501606:IRX3 protein, Xenopus; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D029867:Xenopus Proteins; C484675:Xiro1 protein, Xenopus; D014212:Tretinoin