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991.
Understanding of how the eukaryotic genome is packaged into chromatin and what the functional consequences of this organization
are has begun to emerge recently. The concept of ‘chromatin domains’ — the topologically independent structural unit — is
the basis of higher order chromatin organization. The idea that this structural unit may also coincide with the functional
unit, offers a useful framework in dissecting the structure-function relationship. Boundaries that define these domains have
been identified and several assays have been developed to test themin vivo. We have used genetic means to identify and analyse such boundary elements in the bithorax complex ofDrosophila melanogaster. In this review we discuss chromatin domain boundaries identified in several systems using different means. Although there
is no significant sequence conservation among various chromatin domain boundaries, these elements show functional conservation
across the species. Finally, we discuss mechanistic aspects of how chromatin domain boundaries may function in organizing
and regulating eukaryotic genome. 相似文献
992.
993.
Roser Zaurin Roberto Ferrari Ana Silvina Nacht Jose Carbonell Francois Le
Dily Jofre Font-Mateu Lara
Isabel de
Llobet
Cucalon Enrique Vidal Antonios Lioutas Miguel Beato Guillermo P Vicent 《Nucleic acids research》2021,49(22):12716
Here, we report that in T47D breast cancer cells 50 pM progestin is sufficient to activate cell cycle entry and the progesterone gene expression program. At this concentration, equivalent to the progesterone blood levels found around the menopause, progesterone receptor (PR) binds only to 2800 genomic sites, which are accessible to ATAC cleavage prior to hormone exposure. These highly accessible sites (HAs) are surrounded by well-organized nucleosomes and exhibit breast enhancer features, including estrogen receptor alpha (ERα), higher FOXA1 and BRD4 (bromodomain containing 4) occupancy. Although HAs are enriched in RAD21 and CTCF, PR binding is the driving force for the most robust interactions with hormone-regulated genes. HAs show higher frequency of 3D contacts among themselves than with other PR binding sites, indicating colocalization in similar compartments. Gene regulation via HAs is independent of classical coregulators and ATP-activated remodelers, relying mainly on MAP kinase activation that enables PR nuclear engagement. HAs are also preferentially occupied by PR and ERα in breast cancer xenografts derived from MCF-7 cells as well as from patients, indicating their potential usefulness as targets for therapeutic intervention. 相似文献
994.
995.
Background
Identity by descent (IBD) matrix estimation is a central component in mapping of Quantitative Trait Loci (QTL) using variance component models. A large number of algorithms have been developed for estimation of IBD between individuals in populations at discrete locations in the genome for use in genome scans to detect QTL affecting various traits of interest in experimental animal, human and agricultural pedigrees. Here, we propose a new approach to estimate IBD as continuous functions rather than as discrete values. 相似文献996.
Lionel Leclere Maude Fransolet Francois Cote Pierre Cambier Thierry Arnould Pierre Van Cutsem Carine Michiels 《PloS one》2015,10(3)
Cancer is still one of the leading causes of death worldwide, and finding new treatments remains a major challenge. Previous studies showed that modified forms of pectin, a complex polysaccharide present in the primary plant cell wall, possess anticancer properties. Nevertheless, the mechanism of action of modified pectin and the pathways involved are unclear. Here, we show that citrus pectin modified by heat treatment induced cell death in HepG2 and A549 cells. The induced cell death differs from classical apoptosis because no DNA cleavage was observed. In addition, Z-VAD-fmk, a pan-caspase inhibitor, did not influence the observed cell death in HepG2 cells but appeared to be partly protective in A549 cells, indicating that heat-modified citrus pectin might induce caspase-independent cell death. An increase in the abundance of the phosphatidylethanolamine-conjugated Light Chain 3 (LC3) protein and a decrease in p62 protein abundance were observed in both cell types when incubated in the presence of heat-modified citrus pectin. These results indicate the activation of autophagy. To our knowledge, this is the first time that autophagy has been revealed in cells incubated in the presence of a modified form of pectin. This autophagy activation appears to be protective, at least for A549 cells, because its inhibition with 3-methyladenine increased the observed modified pectin-induced cytotoxicity. This study confirms the potential of modified pectin to improve chemotherapeutic cancer treatments. 相似文献
997.
Francois Raulin 《Origins of life and evolution of the biosphere》2007,37(4-5):345-349
For understanding the origin(s) of life on Earth it is essential to search for and study extraterrestrial environments where
some of the processes which participated in the emergence of Life on our planet are still occurring. This is one of the goals
of astrobiology. In that frame, the study of extraterrestrial organic matter is essential and is certainly not of limited
interest regarding prebiotic molecular evolution. Titan, the largest satellite of Saturn and the only planetary body with
an atmosphere similar to that of the Earth is one of the places of prime interest for these astrobiological questions. It
presents many analogies with the primitive Earth, and is a prebiotic-like laboratory at the planetary scale, where a complex
organic chemistry in is currently going on.
Presented at: International School of Complexity – 4th Course: Basic Questions on the Origins of Life; “Ettore Majorana” Foundation and Centre for Scientific Culture, Erice, Italy, 1–6 October 2006. 相似文献
998.
A simple technique of purification of the soluble pig heart mitochondrial F1-ATPase is described. It consists of removal of extrinsic proteins from mitochondrial membranes before extraction with chloroform and ammonium sulfate fractionation. A high degree of purity, an excellent stability and a good yield are attained after gel filtration through an Ultrogel ACA 34 column equilibrated in the presence of 50% glycerol. The tested properties of the F1-ATPase prepared by this method are similar to those of the same enzyme extracted by sonication. The enzyme is virtually devoid of tightly bound nucleotides. In addition, some characteristics of the behaviour of the β subunit are shown. 相似文献
999.
Francois Boulay Gérard Brandolin Guy J.M. Lauquin Pierre V. Vignais 《Analytical biochemistry》1983,128(2):323-330
The chemical synthesis of fluorescent derivatives of atractyloside (ATR), an inhibitor of the mitochondrial ADP/ATP carrier protein, is described. These derivatives are the following: 6′-O-dansyl ATR, 6′-O-dansyl-aminobutyryl ATR, and 6′-O-naphthoyl ATR. The spectral properties of these analogs were analyzed, and their biological features were compared to those of ATR. The fluorescence emission of the dansyl ATR derivatives was increased in organic solvents and that of naphthoyl ATR was decreased; for both analogs, solubilization in organic solvents resulted in a blue shift of the emission peak. The fluorescent dansyl and naphthoyl ATR derivatives were specifically recognized by the mitochondrial ADP/ATP carrier protein. Because of their spectral properties and their biochemical reactivities, the fluorescent analogs of ATR can be considered as potential probes to investigate the topography of the ADP/ATP carrier in the mitochondrial membrane and to monitor conformational changes of the ADP/ATP carrier protein associated with transport. 相似文献
1000.