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91.
Margolin W 《Cell》2004,117(7):850-851
Prior to its duplication, the bacterial nucleoid exerts local negative control over assembly of the cytokinetic Z ring to prevent potential cutting of the chromosome. In this issue of Cell, Wu and Errington show that a specific nucleoid-associated protein mediates this nucleoid occlusion effect, providing the first mechanistic insight into this key spatial regulatory system. 相似文献
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M S Sachs E U Selker B Lin C J Roberts Z Luo D Vaught-Alexander B S Margolin 《Nucleic acids research》1997,25(12):2389-2395
The expression of thymidine kinase in fungi, which normally lack this enzyme, will greatly aid the study of DNA metabolism and provide useful drug-sensitive phenotypes. The herpes simplex virus type-1 thymidine kinase gene ( tk ) was expressed in Neurospora crassa. tk was expressed as a fusion to N.crassa arg-2 regulatory sequences and as a hygromycin phosphotransferase-thymidine kinase fusion gene under the control of cytomegalovirus and SV40 sequences. Only strains containing tk showed thymidine kinase enzyme activity. In strains containing the arg-2 - tk gene, both the level of enzyme activity and the level of mRNA were reduced by growth in arginine medium, consistent with control through arg-2 regulatory sequences. Expression of thymidine kinase in N.crassa facilitated radioactive labeling of replicating DNA following addition of [3H]thymidine or [14C]thymidine to the growth medium. Thymidine labeling of DNA enabled demonstration that hydroxyurea can be used to block replication and synchronize the N.crassa mitotic cycle. Strains expressing thymidine kinase were also more sensitive than strains lacking thymidine kinase to anticancer and antiviral nucleoside drugs that are activated by thymidine kinase, including 5-fluoro-2'-deoxyuridine, 1-(2-deoxy-2-fluoro-beta-D-arabinofuranosyl)-5-iodouridine and trifluorothymidine. Finally, expression of thymidine kinase in N. crassa enabled incorporation of bromodeoxyuridine into DNA at levels sufficient to separate newly replicated DNA from old DNA using equilibrium centrifugation. 相似文献
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Melanoma central nervous system metastases: current approaches,challenges, and opportunities
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Justine V. Cohen Hussain Tawbi Kim A. Margolin Ravi Amravadi Marcus Bosenberg Priscilla K. Brastianos Veronica L. Chiang John de Groot Isabella C. Glitza Meenhard Herlyn Sheri L. Holmen Lucia B. Jilaveanu Andrew Lassman Stergios Moschos Michael A. Postow Reena Thomas John A. Tsiouris Patrick Wen Richard M. White Timothy Turnham Michael A. Davies Harriet M. Kluger 《Pigment cell & melanoma research》2016,29(6):627-642
Melanoma central nervous system metastases are increasing, and the challenges presented by this patient population remain complex. In December 2015, the Melanoma Research Foundation and the Wistar Institute hosted the First Summit on Melanoma Central Nervous System (CNS) Metastases in Philadelphia, Pennsylvania. Here, we provide a review of the current status of the field of melanoma brain metastasis research; identify key challenges and opportunities for improving the outcomes in patients with melanoma brain metastases; and set a framework to optimize future research in this critical area. 相似文献
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The problem of assessing synergistic or antagonistic departure from simple independent action in multifactor tables of proportions is discussed. A generalized linear model is employed in which additivity corresponds to simple independent action. Data-analytic strategies are proposed for exploring departures from simple independent action in various extensions of the 2 X 2 table of proportions. This methodology is illustrated with a series of models fitted to cellular differentiation and murine toxicity data. 相似文献
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Increased synthesis of the protein FxsA alleviates the exclusion of T7 in cells harboring the F plasmid. In contrast to wild-type or cells defective in fxsA, overexpression of fxsA+ allows T7 to form plaques at normal efficiency even though the burst size is reduced to about half that obtained on the isogenic F- strain. No defect in DNA synthesis was observed but late protein synthesis remains partially inhibited and a reduced level of cell leakiness, a prominent feature of F+ cells abortively infected by T7, persists. The FxsA protein is shown to be a cytoplasmic membrane protein. How T7 avoids exclusion by F in cells that exhibit increased levels of FxsA is discussed in terms of its membrane localization. 相似文献
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FtsZ, a bacterial homolog of eukaryotic tubulin, assembles into the Z ring required for cytokinesis. In Escherichia coli, FtsZ interacts directly with FtsA and ZipA, which tether the Z ring to the membrane. We used three-dimensional structured illumination microscopy to compare the localization patterns of FtsZ, FtsA, and ZipA at high resolution in Escherichia coli cells. We found that FtsZ localizes in patches within a ring structure, similar to the pattern observed in other species, and discovered that FtsA and ZipA mostly colocalize in similar patches. Finally, we observed similar punctate and short polymeric structures of FtsZ distributed throughout the cell after Z rings were disassembled, either as a consequence of normal cytokinesis or upon induction of an endogenous cell division inhibitor. 相似文献