| 1. |
- Baud, Sébastien, et al.
(författare)
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gurke and pasticcino3 mutants affected in embryo development are impaired in acetyl-CoA carboxylase.
- 2004
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Ingår i: EMBO Reports. - : EMBO. - 1469-221X .- 1469-3178. ; 5:5
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Tidskriftsartikel (refereegranskat)abstract
- Normal embryo development is required for correct seedling formation. The Arabidopsis gurke and pasticcino3 mutants were isolated from different developmental screens and the corresponding embryos exhibit severe defects in their apical region, affecting bilateral symmetry. We have recently identified lethal acc1 mutants affected in acetyl-CoA carboxylase 1 (ACCase 1) that display a similar embryo phenotype. A series of crosses showed that gk and pas3 are allelic to acc1 mutants, and direct sequencing of the ACC1 gene revealed point mutations in these new alleles. The isolation of leaky acc1 alleles demonstrated that ACCase 1 is essential for correct plant development and that mutations in ACCase affect cellular division in plants, as is the case in yeast. Interestingly, significant metabolic complementation of the mutant phenotype was obtained by exogenous supply of malonate, suggesting that the lack of cytosolic malonyl-CoA is likely to be the initial factor leading to abnormal development in the acc1 mutants.
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| 2. |
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| 3. |
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| 4. |
- Desnues, B, et al.
(författare)
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Differential oxidative damage and expression of stress defence regulons in culturable and non-culturable Escherichia coli cells
- 2003
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Ingår i: EMBO Reports. - : EMBO. - 1469-221X .- 1469-3178. ; 4:4, s. 400-404
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Tidskriftsartikel (refereegranskat)abstract
- Potentially pathogenic bacteria, such as Escherichia coli and Vibrio cholerae, become non-culturable during stasis. The analysis of such cells has been hampered by difficulties in studying bacterial population heterogeneity. Using in situ detection of protein oxidation in single E. coli cells, and using a density-gradient centrifugation technique to separate culturable and non-culturable cells, we show that the proteins in non-culturable cells show increased and irreversible oxidative damage, which affects various bacterial compartments and proteins. The levels of expression of specific stress regulons are higher in non-culturable cells, confirming increased defects relating to oxidative damage and the occurrence of aberrant, such as by amino-acid misincorporation, proteins. Our data suggest that non-culturable cells are produced due to stochastic deterioration, rather than an adaptive programme, and pinpoint oxidation management as the 'Achilles heel' of these cells.
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| 5. |
- Grenklo, Staffan, et al.
(författare)
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A crucial role for profilin-actin in the intracellular motility of Listeria monocytogenes
- 2003
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Ingår i: EMBO reports. - London : Nature Publishing Group. - 1469-221X .- 1469-3178. ; 4:5, s. 523-529
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Tidskriftsartikel (refereegranskat)abstract
- We have examined the effect of covalently crosslinked profilin–actin (PxA), which closely matches the biochemical properties of ordinary profilin–actin and interferes with actin polymerization in vitro and in vivo, on Listeria monocytogenes motility. PxA caused a marked reduction in bacterial motility, which was accompanied by the detachment of bacterial tails. The effect of PxA was dependent on its binding to proline-rich sequences, as shown by the inability of PH133SxA, which cannot interact with such sequences, to impair Listeria motility. PxA did not alter the motility of a Listeria mutant that is unable to recruit Ena (Enabled)/VASP (vasodilator-stimulated phosphoprotein) proteins and profilin to its surface. Finally, PxA did not block the initiation of actin-tail formation, indicating that profilin–actin is only required for the elongation of actin filaments at the bacterial surface. Our findings provide further evidence that profilin–actin is important for actin-based processes, and show that it has a key function in Listeria motility.
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| 6. |
- Huang, Tien-Sheng, et al.
(författare)
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Functional inactivation of the SR family of splicing factors during a vaccinia virus infection
- 2002
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Ingår i: EMBO Reports. - : EMBO. - 1469-221X .- 1469-3178. ; 3:11, s. 1088-1093
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Tidskriftsartikel (refereegranskat)abstract
- SR proteins are essential splicing factors required for constitutive splicing and function as key regulators of alternative RNA splicing. We have shown that SR proteins purified from late adenovirus-infected cells (SR-Ad) are functionally inactivated as splicing enhancer or splicing repressor proteins by a virus-induced partial de-phosphorylation. Here, we show that SR proteins purified from late vaccinia-virus-infected cells (SR-VV) are also hypo-phosphorylated and functionally inactivated as splicing regulatory proteins. We further show that incubating SR-Ad proteins under conditions that restore the phospho-epitopes to the SR proteins results in the restoration of their activity as splicing enhancer and splicing repressor proteins. Interestingly, re-phosphorylation of SR-VV proteins only partially restored the splicing enhancer or splicing repressor phenotype to the SR proteins. Collectively, our results suggest that viral control of SR protein activity may be a common strategy used by DNA viruses to take control of the host cell RNA splicing machinery.
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| 7. |
- Kurland, Charles
(författare)
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Something for everyone - Horizontal gene transfer in evolution
- 2000
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Ingår i: EMBO Reports. - : EMBO. - 1469-221X .- 1469-3178. ; 1:2, s. 92-95
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Tidskriftsartikel (refereegranskat)abstract
- Horizontal gene transfer (HGT) is a sensational topic largely because its exploitation to date has been primarily journalistic. Properly packaged it captures the attention of a sensitized lay public and peps up circulation. HGT provides technical challenges for academic scientists as well as market analysts. For fans of science fiction as well as for environmental pessimists, HGT is the stuff of doomsday prophecies. Interest in HGT might even be seen as a reasonable response to the recent acquisition of genome sequence data and the need to understand how genomes exchange sequences.
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| 9. |
- Lorén, Christina, et al.
(författare)
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A crucial role for the Anaplastic lymphoma kinase receptor tyrosine kinase in gut development in Drosophila melanogaster
- 2003
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Ingår i: EMBO Reports. - : Nature Publishing Group. - 1469-221X .- 1469-3178. ; 4:8, s. 781-786
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Tidskriftsartikel (refereegranskat)abstract
- The Drosophila melanogaster gene Anaplastic lymphoma kinase (Alk) is homologous to mammalian Alk, which encodes a member of the Alk/Ltk family of receptor tyrosine kinases (RTKs). In humans, the t(2;5) translocation, which involves the ALK locus, produces an active form of ALK, which is the causative agent in non-Hodgkin's lymphoma. The physiological function of the Alk RTK, however, is unknown. In this paper, we describe loss-of-function mutants in the Drosophila Alk gene that cause a complete failure of the development of the gut. We propose that the main function of Drosophila Alk during early embryogenesis is in visceral mesoderm development.
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| 10. |
- Ober, Elke A, et al.
(författare)
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Vegfc is required for vascular development and endoderm morphogenesis in zebrafish.
- 2004
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Ingår i: EMBO Reports. - : EMBO. - 1469-221X .- 1469-3178. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- During embryogenesis, complex morphogenetic events lead endodermal cells to coalesce at the midline and form the primitive gut tube and associated organs. While several genes have recently been implicated in endoderm differentiation, we know little about the genes that regulate endodermal morphogenesis. Here, we show that vascular endothelial growth factor C (Vegfc), an angiogenic as well as a lymphangiogenic factor, is unexpectedly involved in this process in zebrafish. Reducing Vegfc levels using morpholino antisense oligonucleotides, or through overexpression of a soluble form of the VEGFC receptor, VEGFR-3, affects the coalescence of endodermal cells in the anterior midline, leading to the formation of a forked gut tube and the duplication of the liver and pancreatic buds. Further analyses indicate that Vegfc is additionally required for the initial formation of the dorsal endoderm. We also demonstrate that Vegfc is required for vasculogenesis as well as angiogenesis in the zebrafish embryo. These data argue for a requirement of Vegfc in the developing vasculature and, more surprisingly, implicate Vegfc signalling in two distinct steps during endoderm development, first during the initial differentiation of the dorsal endoderm, and second in the coalescence of the anterior endoderm to the midline.
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