Premium
Thymopoiesis requires Pax9 function in thymic epithelial cells
Author(s) -
HetzerEgger Claudia,
Schorpp Michael,
HaasAssenbaum Annette,
Balling Rudi,
Peters Heiko,
Boehm Thomas
Publication year - 2002
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/1521-4141(200204)32:4<1175::aid-immu1175>3.0.co;2-u
Subject(s) - biology , pharyngeal pouch , endoderm , progenitor , epithelium , progenitor cell , ectopic expression , embryonic stem cell , lymphatic system , microbiology and biotechnology , foregut , gene , anatomy , stem cell , immunology , genetics
Abstract The epithelial thymic anlage develops from the third pharyngeal pouch. Pax9 is expressed in the entire pharyngeal endoderm, and its function is required for normal development of organs derived from pharyngeal pouches. Here, we show that in Pax9 null mice, the thymic anlage develops as an ectopic polyp‐like structure in the larynx. It expresses Whn/Foxn1 , a marker of thymic epithelium, but fails to perform the normal caudo‐ventral movement to the upper mediastinum. The thymic rudiment contains mesenchymal cells, blood vessels and is colonized by T cell progenitors. However, from embryonic day 14.5 onwards, the size of the Pax9 mutant thymus is severely reduced. Whereas expression of TCRβ chain genes is readily detectable in the mutant thymus, noexpression of the TCRγ chain was detectable. Our results identify a new genetically defined control point of thymopoiesis.