The morpho-structural characteristics of the vallate papillae of the tongue of rat, dog, donkey and buffalo were investigated by macroscopy and their microstructure by light and scanning electron microscopy (SEM). The numbers of vallate papillae varied among the different species. In rat, a single vallate papilla surrounded by incomplete groove and an annular fold was observed. Taste buds were detected along the entire length of the medial and lateral groove epithelium, but not in the papillary dome. In dog, some papillae lacking the annular pad had irregular ridges and grooves toward the center of the papillary surface, while other papillae had small secondary papillary grooves arising from the center of the papilla. Taste buds were located in the medial and lateral epithelium of both primary and secondary grooves as well as in the dome epithelium. In donkey, two papillae were frequently observed around the midline of the tongue root, and an additional papilla was found occasionally in the middle and associated with secondary papilla. In buffalo, several papillae were relatively small and variable in shape. With SEM, small ridges and grooves were found in the papillae of donkey and buffalo. In both species, taste buds were constantly observed along the medial wall epithelium, but no taste buds were found in the lateral wall. We conclude that the vallate papillae exhibited peculiar characteristics, which are species specific and might have a correlation with the variable feeding habits among these animals.

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Kruppel-like factor 4 (KLF4) is a zinc finger transcription factor that plays crucial roles during the development and maintenance of multiple organs. We and others have previously shown that KLF4 is involved in bone modeling and remodeling but roles played by KLF4 during skeletogenesis are still not fully understood. Here, we show that KLF4 is expressed in the epiphyseal growth plate and articular chondrocytes. Most articular chondrocytes expressed KLF4 in embryos but it localized only in a subset of superficial zone cells in postnatal mice. When KLF4 was overexpressed in chondrocytes in vitro, it severely repressed chondrocytic gene expressions. Global gene expression profiling of KLF4-transduced chondrocytes revealed matrix degrading proteinases of the matrix metalloproteinase and disintegrin and metalloproteinase with thrombospondin-1 domain families within the group of upregulated genes. Proteinase induction by KLF4 was alleviated by Trichostatin A treatment suggesting the possible involvement of epigenetic mechanisms on proteinase induction by KLF4. These results indicate the possible involvement of KLF4 in physiological and pathological aspects during cartilage development and maintenance.

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.

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