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11.
Relief of hypoxia by angiogenesis promotes neural stem cell differentiation by targeting glycolysis 下载免费PDF全文
Christian Lange Miguel Turrero Garcia Ilaria Decimo Francesco Bifari Guy Eelen Annelies Quaegebeur Ruben Boon Hui Zhao Bram Boeckx Junlei Chang Christine Wu Ferdinand Le Noble Diether Lambrechts Mieke Dewerchin Calvin J Kuo Wieland B Huttner Peter Carmeliet 《The EMBO journal》2016,35(9):924-941
Blood vessels are part of the stem cell niche in the developing cerebral cortex, but their in vivo role in controlling the expansion and differentiation of neural stem cells (NSCs) in development has not been studied. Here, we report that relief of hypoxia in the developing cerebral cortex by ingrowth of blood vessels temporo‐spatially coincided with NSC differentiation. Selective perturbation of brain angiogenesis in vessel‐specific Gpr124 null embryos, which prevented the relief from hypoxia, increased NSC expansion at the expense of differentiation. Conversely, exposure to increased oxygen levels rescued NSC differentiation in Gpr124 null embryos and increased it further in WT embryos, suggesting that niche blood vessels regulate NSC differentiation at least in part by providing oxygen. Consistent herewith, hypoxia‐inducible factor (HIF)‐1α levels controlled the switch of NSC expansion to differentiation. Finally, we provide evidence that high glycolytic activity of NSCs is required to prevent their precocious differentiation in vivo. Thus, blood vessel function is required for efficient NSC differentiation in the developing cerebral cortex by providing oxygen and possibly regulating NSC metabolism. 相似文献
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Kristen Fernandes Mieke van der Heyde Megan Coghlan Grant Wardell‐Johnson Michael Bunce Richard Harris Paul Nevill 《Restoration Ecology》2019,27(5):1177-1186
Invertebrate biomonitoring can reveal crucial information about the status of restoration projects; however, it is routinely underused because of the high level of taxonomic expertise and resources required. Invertebrate DNA metabarcoding has been used to characterize invertebrate biodiversity but its application in restoration remains untested. We use DNA metabarcoding, a new approach for restoration assessment, to explore the invertebrate composition from pitfall traps at two mine site restoration chronosequences in southwestern Australia. Invertebrates were profiled using two cytochrome oxidase subunit 1 assays to investigate invertebrate biodiversity. The data revealed differences between invertebrate communities at the two mines and between the different age plots of the chronosequences. Several characteristic taxa were identified for each age within the chronosequence, including springtails within the youngest sites (Order: Collembola) and millipedes within the oldest and reference sites (Order: Julida). This study facilitates development of a molecular “toolkit” for the monitoring of ecological restoration projects. We suggest that a metabarcoding approach shows promise in complementing current monitoring practices that rely on alpha taxonomy. 相似文献
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Mieke M. E. Huijbers Jenny W. Wu Adrie H. Westphal Willem J. H. van Berkel 《Biotechnology journal》2019,14(5)
Thermus thermophilus proline dehydrogenase ( TtProDH) catalyzes the first step in proline catabolism. The thermostable flavoenzyme consists of a distorted triosephosphate isomerase (TIM) barrel and three N‐terminal helices: αA, αB, and αC. Using maltose‐binding protein (MBP) fused constructs, it has been recently demonstrated that helix αC is crucial for TtProDH catalysis and for tetramerization through positioning of helix α8. Here, the structural features that determine the thermostability of TtProDH are reported. Selective disruption of two ion pairs in the dimerization interface of several MBP‐TtProDH variants result in the formation of monomers. The newly created monomers have improved catalytic properties but their melting temperatures are decreased by more than 20 °C. Sequence comparison suggests that one of the ion‐pairs involved in dimerization is unique for ProDHs from Thermus species. In summary, intermolecular ion‐pairs improve the thermostability of TtProDH and a trade‐off is made between thermostability and catalytic activity. 相似文献
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Rab27b is up-regulated in human Griscelli syndrome type II melanocytes and linked to the actin cytoskeleton via exon F-Myosin Va transcripts 总被引:1,自引:0,他引:1
16.
Interactions between ethylene and gibberellins in phytochrome-mediated shade avoidance responses in tobacco 总被引:14,自引:0,他引:14 下载免费PDF全文
Plants respond to proximate neighbors with a suite of responses that comprise the shade avoidance syndrome. These phytochrome-mediated responses include hyponasty (i.e. a more vertical orientation of leaves) and enhanced stem and petiole elongation. We showed recently that ethylene-insensitive tobacco (Nicotiana tabacum) plants (Tetr) have reduced responses to neighbors, showing an important role for this gaseous plant hormone in shade avoidance. Here, we investigate interactions between phytochrome signaling and ethylene action in shade avoidance responses. Furthermore, we investigate if ethylene acts in these responses through an interaction with the GA class of hormones. Low red to far-red light ratios (R:FR) enhanced ethylene production in wild-type tobacco, resulting in shade avoidance responses, whereas ethylene-insensitive plants showed reduced shade avoidance responses. Plants with inhibited GA production showed hardly any shade avoidance responses at all to either a low R:FR or increased ethylene concentrations. Furthermore, low R:FR enhanced the responsiveness of hyponasty and stem elongation in both wild-type and Tetr plants to applied GA(3), with the stem elongation process being more responsive to GA(3) in the wild type than in Tetr. We conclude that phytochrome-mediated shade avoidance responses involve ethylene action, at least partly by modulating GA action. 相似文献
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Mulder J Poland M Gebbink MF Calafat J Moolenaar WH Kranenburg O 《The Journal of biological chemistry》2003,278(29):27216-27223
p116Rip is a ubiquitously expressed protein that was originally identified as a putative binding partner of RhoA in a yeast two-hybrid screen. Overexpression of p116Rip in neuroblastoma cells inhibits RhoA-mediated cell contraction induced by lysophosphatidic acid (LPA); so far, however, the function of p116Rip is unknown. Here we report that p116Rip localizes to filamentous actin (F-actin)-rich structures, including stress fibers and cortical microfilaments, in both serum-deprived and LPA-stimulated cells, with the N terminus (residues 1-382) dictating cytoskeletal localization. In addition, p116Rip is found in the nucleus. Direct interaction or colocalization with RhoA was not detected. We find that p116Rip binds tightly to F-actin (Kd approximately 0.5 microm) via its N-terminal region, while immunoprecipitation assays show that p116Rip is complexed to both F-actin and myosin-II. Purified p116Rip and the F-actin-binding region can bundle F-actin in vitro, as shown by electron microscopy. When overexpressed in NIH3T3 cells, p116Rip disrupts stress fibers and promotes formation of dendrite-like extensions through its N-terminal actin-binding domain; furthermore, overexpressed p116Rip inhibits growth factor-induced lamellipodia formation. Our results indicate that p116Rip is an F-actin-binding protein with in vitro bundling activity and in vivo capability of disassembling the actomyosin-based cytoskeleton. 相似文献
20.
Inge Decorte Mieke Steensels Bénédicte Lambrecht Ann Brigitte Cay Nick De Regge 《PloS one》2015,10(10)