84 research outputs found
Heat and water stress induce unique transcriptional signatures of heat-shock proteins and transcription factors in grapevine
Grapevine is an extremely important crop worldwide.
In southern Europe, post-flowering phases of the growth
cycle can occur under high temperatures, excessive light, and
drought conditions at soil and/or atmospheric level. In this
study, we subjected greenhouse grown grapevine, variety
Aragonez, to two individual abiotic stresses, water deficit stress
(WDS), and heat stress (HS). The adaptation of plants to stress
is a complex response triggered by cascades of molecular
networks involved in stress perception, signal transduction,
and the expression of specific stress-related genes and metabolites.
Approaches such as array-based transcript profiling allow
assessing the expression of thousands of genes in control
and stress tissues. Using microarrays, we analyzed the leaf
transcriptomic profile of the grapevine plants. Photosynthesis
measurements verified that the plants were significantly affected
by the stresses applied. Leaf gene expression was obtained
using a high-throughput transcriptomic grapevine array, the
23K custom-made Affymetrix Vitis GeneChip. We identified
1,594 genes as differentially expressed between control and
treatments and grouped them into ten major functional categories
using MapMan software. The transcriptome of Aragonez
was more significantly affected by HS when compared with
WDS. The number of genes coding for heat-shock proteins and
transcription factors expressed solely in response to HS suggesting
their expression as unique signatures of HS. However, a cross-talk between the response pathways to both stresses was
observed at the level of AP2/ERF transcription factors
Defining the structure of membrane-bound human blood coagulation factor Va
Background: Blood coagulation factor (F) Va is the essential protein cofactor to the serine protease FXa. Factor Va stimulates the thrombin-to-prothrombin conversion by the prothrombinase complex, by at least five orders of magnitude. Factor Va binds with very high affinity to phosphatidylserine containing phospholipid membranes, which allows the visualization of its membrane-bound state by transmission electron microscopy (EM). Methods: In this paper we present an averaged three-dimensional structure of FVa molecules attached to phosphatidylserine containing lipid tubes, as determined by EM and single particle analysis. The low-resolution FVa three-dimensional structure is compared with the available atomic models for FVa. Results: The experimental data are combined with the most suitable atomic model and a membrane-bound FVaEM model is proposed that best fits the protein density defined by EM. In the FVaEM model, the C1 and C2 membrane-binding domains are juxtaposed onto the membrane surface and the model geometries indicate a deeper insertion of both C domains into the lipid bilayer than has been previously suggested. Conclusion: The present structure is a first step towards a higher-resolution experimental structure of a human FVa molecule in its membrane-bound conformation, allowing the visualization of individual domains within FVa and its association with the membrane
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