Analysis of grain characters in temperate grasses reveals distinctive patterns of endosperm organization associated with grain shape.

Members of the core pooids represent the most important crops in temperate zones including wheat, barley, and oats. Their importance as crops is largely due to the grain, particularly the storage capabilities of the endosperm. In this study, a comprehensive survey of grain morphology and endosperm organization in representatives of wild and cultivated species throughout the core pooids was performed. As sister to the core pooid tribes Poeae, Aveneae, Triticeae, and Bromeae within the Pooideae subfamily, Brachypodium provides a taxonomically relevant reference point. Using macroscopic, histological, and molecular analyses distinct patterns of grain tissue organization in these species, focusing on the peripheral and modified aleurone, are described. The results indicate that aleurone organization is correlated with conventional grain quality characters such as grain shape and starch content. In addition to morphological and organizational variation, expression patterns of candidate gene markers underpinning this variation were examined. Features commonly associated with grains are largely defined by analyses on lineages within the Triticeae and knowledge of grain structure may be skewed as a result of the focus on wheat and barley. Specifically, the data suggest that the modified aleurone is largely restricted to species in the Triticeae tribe.

Lack of a fusion requirement for development of bone marrow-derived epithelia.

Analysis of developmental plasticity of bone marrow-derived cells (BMDCs) is complicated by the possibility of cell-cell fusion. Here we demonstrate that epithelial cells can develop from BMDCs without cell-cell fusion. We use the Cre/lox system together with beta-galactosidase and enhanced green fluorescent protein expression in transgenic mice to identify epithelial cells in the lung, liver, and skin that develop from BMDCs without cell fusion.

The expression of the developmentally regulated proto-oncogene Pax-3 is modulated by N-Myc.

N-Myc is a member of the Myc family of transcription factors that have been shown to play a pivotal role in cell proliferation and differentiation. In this report, we have investigated the relationship between N-Myc and the developmental control gene Pax-3. Using transient transfection assays, we show that the Pax-3 promoter is activated by both N-Myc-Max and c-Myc-Max. Moreover, we show that Myc regulation of Pax-3 promoter activity is dependent upon a noncanonical E box site in the 5' promoter region of Pax-3. In addition, we show that ectopic expression of both N-Myc and c-Myc leads to increased expression of Pax-3 mRNA. Furthermore, we show that Pax-3 mRNA expression is cell cycle-regulated and that the 5' promoter region of Pax-3 (bp -1578 to +56) can direct cell cycle-dependent gene expression with kinetics similar to that of the endogenous transcript. Site-directed mutagenesis of the E box site within the Pax-3 promoter significantly altered the pattern of expression through the cell cycle. These results suggest that the Myc family of transcription factors may modulate Pax-3 expression in vivo.