386 research outputs found
In silico and in vivo identification of the intermediate filament vimentin that is downregulated downstream of Brachyury during Xenopus embryogenesis
No full textBrachyury, a member of the T-box transcription family, has been suggested to be essential for morphogenetic movements in various processes of animal development. However, little is known about its critical transcriptional targets. In order to identify targets of Brachyury and understand the molecular mechanisms underlying morphogenetic movements, we first searched the genome sequence of Xenopus tropicalis, the only amphibian genomic sequence available, for Brachyury-binding sequences known as T-half sites, and then screened for the ones conserved between vertebrate genomes. We found three genes that have evolutionarily conserved T-half sites in the promoter regions and examined these genes experimentally to determine whether their expressions were regulated by Brachyury, using the animal cap system of Xenopus laevis embryos. Eventually, we obtained evidence that vimentin, encoding an intermediate filament protein, was a potential target of Brachyury. This is the first report to demonstrate that Brachyury might affect the cytoskeletal structure through regulating the expression of an intermediate filament protein, vimentin
Emperor Yung-chêｎg and "Ta-i Chüeh-mi Lu"(大義覺迷錄)
No full textThe Ta-i Chueh-mi Lu was published by Emperor Yung-cheng, who became much concerned with the Tseng Ching (曽静) affair. The Tseng Ching affair was motivated by the thought of Lu Liu-liang (呂留良) on the "difference between the Chinese and the Barbarians" and "Kingly Goverment." What was Lu Liu-liang's thought? How Tseng Ching became influenced by his thought? The Tseng China affair was also due to the rivalries between the cliques within the Ch'ing court. What was Emperor Yung-cheng's attitude toward the rivalries? The author tries to show that the Ta-i Chueh-mi Lu, which was written for the sake of guiding the people's thought, was at the same time intended to give Yung-cheng's view on these rivalries
Interregional Coevolution Analysis Revealing Functional and Structural Interrelatedness between Different Genomic Regions in Human Mastadenovirus D
No full textHuman mastadenovirus D (HAdV-D) is exceptionally rich in type among the seven human adenovirus species. This feature is attributed to frequent intertypic recombination events that have reshuffled orthologous genomic regions between different HAdV-D types. However, this trend appears to be paradoxical, as it has been demonstrated that the replacement of some of the interacting proteins for a specific function with other orthologues causes malfunction, indicating that intertypic recombination events may be deleterious. In order to understand why the paradoxical trend has been possible in HAdV-D evolution, we conducted an interregional coevolution analysis between different genomic regions of 45 different HAdV-D types and found that ca. 70% of the genome has coevolved, even though these are fragmented into several pieces via short intertypic recombination hot spot regions. Since it is statistically and biologically unlikely that all of the coevolving fragments have synchronously recombined between different genomes, it is probable that these regions have stayed in their original genomes during evolution as a platform for frequent intertypic recombination events in limited regions. It is also unlikely that the same genomic regions have remained almost untouched during frequent recombination events, independently, in all different types, by chance. In addition, the coevolving regions contain the coding regions of physically interacting proteins for important functions. Therefore, the coevolution of these regions should be attributed at least in part to natural selection due to common biological constraints operating on all types, including protein-protein interactions for essential functions. Our results predict additional unknown protein interactions. IMPORTANCE Human mastadenovirus D, an exceptionally type-rich human adenovirus species and causative agent of different diseases in a wide variety of tissues, including that of ocular region and digestive tract, as well as an opportunistic infection in immunocompromised patients, is known to have highly diverged through frequent intertypic recombination events; however, it has also been demonstrated that the replacement of a component protein of a multiprotein system with a homologous protein causes malfunction. The present study solved this apparent paradox by looking at which genomic parts have coevolved using a newly developed method. The results revealed that intertypic recombination events have occurred in limited genomic regions and been avoided in the genomic regions encoding proteins that physically interact for a given function. This approach detects purifying selection against recombination events causing the replacement of partial components of multiprotein systems and therefore predicts physical and functional interactions between different proteins and/or genomic elements
Mechanical properties of Al2O3 reinforced by dispersion of metal-particles. II. Dispersion via electroless plating procedure.
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