Cell density regulates many aspects of cell properties and behaviors including metabolism, growth, cytoskeletal structure and locomotion. Importantly, the responses by cultured cells to density signals also uncover key mechanisms that govern animal development and diseases in vivo. Here we characterized a density-responsive reporter system in transgenic Drosophila S2 cells.
View Article and Find Full Text PDFThe three-dimensional organization of the eukaryotic genome is important for its structure and function. Recent studies indicate that hierarchies of chromatin loops underlie important aspects of both genomic organization and gene regulation. Looping between insulator or boundary elements interferes with enhancer-promoter communications and limits the spread active or repressive organized chromatin.
View Article and Find Full Text PDFThe three-dimensional (3D) organization of the eukaryotic genome is critical for its proper function. Evidence suggests that extensive chromatin loops form the building blocks of the genomic architecture, separating genes and gene clusters into distinct functional domains. These loops are anchored in part by a special type of DNA elements called chromatin boundary elements (CBEs).
View Article and Find Full Text PDFChromatin boundary elements (CBEs) are widely distributed in the genome and mediate formation of chromatin loops, but their roles in gene regulation remain poorly understood. The complex expression pattern of the Drosophila homeotic gene Sex combs reduced (Scr) is directed by an unusually long regulatory sequence harboring diverse cis elements and an intervening neighbor gene fushi tarazu (ftz). Here we report the presence of a multitude of CBEs in the Scr regulatory region.
View Article and Find Full Text PDFStudying development in diverse taxa can address a central issue in evolutionary biology: how morphological diversity arises through the evolution of developmental mechanisms. Two of the best-studied developmental model organisms, the arthropod Drosophila and the nematode Caenorhabditis elegans, have been found to belong to a single protostome superclade, the Ecdysozoa. This finding suggests that a closely related ecdysozoan phylum could serve as a valuable model for studying how developmental mechanisms evolve in ways that can produce diverse body plans.
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