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Origin of the ultimobranchial body cyst: T/ebp/Nkx2.1 expression is required for development and fusion of the ultimobranchial body to the thyroid
Author(s) -
Kusakabe Takashi,
Hoshi Nobuo,
Kimura Shioko
Publication year - 2006
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.20655
Subject(s) - biology , thyroid , anatomy , expression (computer science) , medicine , endocrinology , computer science , programming language
Abstract The ultimobranchial body (UBB) is an outpocketing of the fourth pharyngeal pouch that fuses with the thyroid diverticulum, giving rise to calcitonin‐producing C‐cells. In this study, we demonstrate that the UBB is composed of two types of cells: one expressing T/ebp/Nkx2.1 and the other expressing p63. The former cell type, accounting for a majority of the UBB, requires T/ebp/Nkx2.1 for their survival. In contrast, the p63‐positive cells, even in the absence of T/ebp/Nkx2.1 expression, can proliferate and give rise to a vesicular structure that is lined by a monolayer of p63‐negative cells, surrounded by a cluster and/or single layer of p63‐positive cells, displaying the basal/stem cell phenotype. T/ebp/Nkx2.1 haploinsufficiency causes abnormal fusion of the UBB with the thyroid diverticulum, which stays as a cluster of C‐cells around the vesicular structure, similar to the one observed in mice null for T/ebp/Nkx2.1 expression. These results demonstrate that T/ebp/Nkx2.1 plays a role in the survival of UBB cells, their dissemination into the thyroid diverticulum, and the formation of UBB‐derived vesicular structure. Developmental Dynamics 235:1300–1309, 2006. © 2005 Wiley‐Liss, Inc.