title: Role of Tbx2 in defining the territory of the pronephric nephron.
abstract: Despite extensive study of the development of the nephron, which is the functional unit of the kidney, the molecular mechanisms underlying the determination of nephron size remain largely unknown. Using the Xenopus pronephros, we demonstrate here that Tbx2, a T-box transcriptional repressor, functions to demarcate the territory of the pronephric nephron. Tbx2 is specifically expressed around three distinct components of the pronephric nephron: the tubule, duct and glomus. Gain of function of Tbx2 inhibits nephric mesoderm formation. Conversely, Tbx2 loss of function expands the boundary of each component of the pronephric nephron, resulting in an enlarged pronephros. BMP signals induce Tbx2 in the non-nephric mesoderm, which inhibits the expression of the nephric markers Hey1 and Gremlin. Importantly, these pronephric molecules repress Tbx2 expression by antagonizing BMP signals in the nephric mesoderm. These results suggest that the negative regulatory loops between BMP/Tbx2 and Gremlin or Hey1 are responsible for defining the territory of the pronephric nephron.
authors.affiliation: Division of Molecular and Life Sciences, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk, Republic of Korea.
authors.forename: Gun-Sik
authors.initials: GS
authors.lastname: Cho
authors.forename: Sun-Cheol
authors.initials: SC
authors.lastname: Choi
authors.forename: Edmond Changkyun
authors.initials: EC
authors.lastname: Park
authors.forename: Jin-Kwan
authors.initials: JK
authors.lastname: Han
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism; D016207:Cytokines; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D007678:Kidney Glomerulus / Q000196:embryology / Q000378:metabolism; D007684:Kidney Tubules / Q000196:embryology / Q000378:metabolism; D009399:Nephrons / Q000196:embryology / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D019485:Bone Morphogenetic Proteins; D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins; D012097:Repressor Proteins; D020825:T-Box Domain Proteins; D029867:Xenopus Proteins; C486400:GREM1 protein, Xenopus; C405694:Hairy, HRT1 protein; C097348:T-Box Domain Protein 2