Fate mapping of Trps1 daughter cells during cardiac development using novel Trps1-Cre mice

Tricho-rhino-phalangeal syndrome (TRPS) is a rare congenital disorder that is characterized by abnormal hair growth and skeletal deformities. These result in sparse hair, short stature, and early onset of joint problems. Recent reports have shown that a relatively high proportion of patients with TRPS exhibit a broad range of congenital heart defects. To determine the regulation of Trps1 transcription in vivo, we generated novel transgenic mice, which expressed Cre recombinase under the murine Trps1 proximal promoter sequence (Trps1-Cre). We crossed these mice with Cre reporter mice to identify Trps1 daughter cells. Labeled cells were observed in the appendicular joint tissue, dermal papilla of the hair follicles, cardiac valves, aortic sinus, atrial walls, and the interventricular septum. In situ analysis showed restricted Trps1 expression, which was observed in endocardial cushions of the outflow tract, and in leaflets of all mature cardiac valves. These results suggest that the Trps1 proximal promoter sequence contains some of the tissue-specific Trps1 regulatory region. Further, our findings partially explain why patients with TRPS show a broad range of congenital cardiac defects, although Trps1 expression is observed in a more restricted fashion. genesis 54:379-388, 2016. © 2016 Wiley Periodicals, Inc.