Systematic analysis of cell-cycle gene expression during Arabidopsis development.

The steady-state distribution of cell-cycle transcripts in Arabidopsis thaliana seedlings was studied in a broad in situ survey to provide a better understanding of the expression of cell-cycle genes during plant development. The 61 core cell-cycle genes analyzed were expressed at variable levels throughout the different plant tissues: 23 genes generally in dividing and young differentiating tissues, 34 genes mostly in both dividing and differentiated tissues and four gene transcripts primarily in differentiated tissues. Only 21 genes had a typical patchy expression pattern, indicating tight cell-cycle regulation.

Auxin and other signals on the move in plants.

As multicellular organisms, plants, like animals, use endogenous signaling molecules to coordinate their own physiology and development. To compensate for the absence of a cardiovascular system, plants have evolved specialized transport pathways to distribute signals and nutrients. The main transport streams include the xylem flow of the nutrients from the root to the shoot and the phloem flow of materials from the photosynthetic active tissues.

AMP-activated protein kinase (AMPK) molecular crossroad for metabolic control and survival of neurons.

AMP-activated protein kinase (AMPK) constitutes a molecular hub for cellular metabolic control, common to all eukaryotic cells. Numerous reports have established how AMPK responds to changes in the AMP:ATP ratio as a measure of cellular energy levels. In this way, it integrates control over a number of metabolic enzymes and adapts cellular processes to the current energy status in various cell types, such as muscle and liver cells.

The NBPF1 promoter has been recruited from the unrelated EVI5 gene before simian radiation.

Most new genes arise through the duplication of existing genes. In most cases, the duplication is not limited to the coding sequence but encompasses the regulatory region as well. The NBPF gene family has expanded during recent primate evolution, and it has no known mouse ortholog.

Fluorescence imaging-based screen identifies ARF GEF component of early endosomal trafficking.

Endocytic vesicle trafficking is crucial for regulating activity and localization of plasma membrane components, but the process is still poorly genetically defined in plants. Membrane proteins of the PIN-FORMED (PIN) family exhibit polar localization in plant cells and facilitate cellular efflux of the plant hormone auxin, thereby regulating multiple developmental processes. PIN proteins undergo constitutive endocytosis and GNOM ARF GEF-dependent recycling, and their localization is under extensive regulation by developmental and environmental cues.

Atypical E2Fs: new players in the E2F transcription factor family.

As major regulators of the cell cycle, apoptosis and differentiation, E2F transcription factors have been studied extensively in a broad range of organisms. The recent identification of atypical E2F family members further expands our structural, functional and molecular view of the cellular E2F activity. Unlike other family members, atypical E2Fs have a duplicated DNA-binding domain and control gene expression without heterodimerization with dimerization partner proteins.

Production of antibody fragments in Arabidopsis seeds.

Plants offer a number of attractive benefits over conventional mammalian or bacterial cell culture systems for the production of valuable pharmaceutical and industrial proteins. Currently, antibodies and their derived fragments represent the largest and most important group of biotechnological products in clinical trials. In particular, single-chain antibodies are an interesting class of biopharmaceuticals because they are able to overcome specific problems associated with full-length antibodies.

GlycoFibroTest is a highly performant liver fibrosis biomarker derived from DNA sequencer-based serum protein glycomics.

Liver fibrosis is currently assessed by liver biopsy, a costly and rather cumbersome procedure that is unsuitable for frequent patient monitoring, which drives research into biomarkers for this purpose. To investigate whether the serum N-glycome contains information suitable for this goal, we developed a 96-well plate-based serum N-glycomics sample preparation protocol that only involves fluid transfer steps and incubations in a PCR thermocycler yielding 8-aminopyrene-1,3,6-trisulfonic acid-labeled N-glycans. These N-glycans are then ready for analysis on the capillary electrophoresis-based DNA sequencers that are the current standard in clinical genetics laboratories worldwide.

David and Goliath: what can the tiny weed Arabidopsis teach us to improve biomass production in crops?

In the next decades, the world market for plant-derived products is expected to expand exponentially. Not only do we rely on plants to feed the growing world population, but plants will also play a pivotal role in providing a significant part of our increasing energy demands. Whereas in the 1960s the green revolution contributed to increase plant productivity, it is expected that biotechnological advances will further boost biomass production and plant yield.

Plant CLE peptides from two distinct functional classes synergistically induce division of vascular cells.

The Clavata3 (CLV3)/endosperm surrounding region (CLE) signaling peptides are encoded in large plant gene families. CLV3 and the other A-type CLE peptides promote cell differentiation in root and shoot apical meristems, whereas the B-type peptides (CLE41-CLE44) do not. Instead, CLE41 inhibits the differentiation of Zinnia elegans tracheary elements.

DNA stress checkpoint control and plant development.

Plants are sedentary, and so have unavoidably close contact with agents that target their genome integrity. To sense and react to these threats, plants have evolved DNA stress checkpoint mechanisms that arrest the cell cycle and activate the DNA repair machinery to preserve the genome content. Although the pathways that maintain DNA integrity are largely conserved among eukaryotic organisms, plants put different accents on cell cycle control under DNA stress and might have their own way to cope with it.

Receptor-like kinase ACR4 restricts formative cell divisions in the Arabidopsis root.

During the development of multicellular organisms, organogenesis and pattern formation depend on formative divisions to specify and maintain pools of stem cells. In higher plants, these activities are essential to shape the final root architecture because the functioning of root apical meristems and the de novo formation of lateral roots entirely rely on it. We used transcript profiling on sorted pericycle cells undergoing lateral root initiation to identify the receptor-like kinase ACR4 of Arabidopsis as a key factor both in promoting formative cell divisions in the pericycle and in constraining the number of these divisions once organogenesis has been started.

Analysis of protein processing by N-terminal proteomics reveals novel species-specific substrate determinants of granzyme B orthologs.

Using a targeted peptide-centric proteomics approach, we performed in vitro protease substrate profiling of the apoptotic serine protease granzyme B resulting in the delineation of more than 800 cleavage sites in 322 human and 282 mouse substrates, encompassing the known substrates Bid, caspase-7, lupus La protein, and fibrillarin. Triple SILAC (stable isotope labeling by amino acids in cell culture) further permitted intra-experimental evaluation of species-specific variations in substrate selection by the mouse or human granzyme B ortholog. For the first time granzyme B substrate specificities were directly mapped on a proteomic scale and revealed unknown cleavage specificities, uncharacterized extended specificity profiles, and macromolecular determinants in substrate selection that were confirmed by molecular modeling.

Fine-tuning of early events in the jasmonate response.

Jasmonates (JAs) control many aspects of plant defense and development, for instance by inhibiting growth and eliciting secondary metabolism. The mechanisms by which JAs regulate these processes are currently under intensive investigation. Examination of transcriptional changes upon methyl jasmonate (MeJA) perception in a fast-growing Arabidopsis thaliana cell suspension culture revealed a quick and direct dual effect of JAs on the plant's cellular processes.

Hormone interactions at the root apical meristem.

Plants exhibit an amazing developmental flexibility. Plant embryogenesis results in the establishment of a simple apical-basal axis represented by apical shoot and basal root meristems. Later, during postembryonic growth, shaping of the plant body continues by the formation and activation of numerous adjacent meristems that give rise to lateral shoot branches, leaves, flowers, or lateral roots.

Drosophila alicorn is a neuronal maintenance factor protecting against activity-induced retinal degeneration.

Exploring mechanisms that govern neuronal responses to metabolic stress is essential for the development of therapeutic strategies aimed at treatment of neuronal injury and disease. AMP-activated protein kinase (AMPK) is a key enzyme regulating cellular energy homeostasis that responds to changes in cellular energy levels by promoting energy-restorative and inhibiting energy-consumptive processes. Recent studies have suggested that AMPK might have a neuroprotective function.

Granulin mutations associated with frontotemporal lobar degeneration and related disorders: an update.

Mutations in the gene encoding granulin (HUGO gene symbol GRN, also referred to as progranulin, PGRN), located at chromosome 17q21, were recently linked to tau-negative ubiquitin-positive frontotemporal lobar degeneration (FTLDU). Since then, 63 heterozygous mutations were identified in 163 families worldwide, all leading to loss of functional GRN, implicating a haploinsufficiency mechanism. Together, these mutations explained 5 to 10% of FTLD.

Axonal injury and regeneration in the adult brain of Drosophila.

Drosophila melanogaster is a leading genetic model system in nervous system development and disease research. Using the power of fly genetics in traumatic axonal injury research will significantly speed up the characterization of molecular processes that control axonal regeneration in the CNS. We developed a versatile and physiologically robust preparation for the long-term culture of the whole Drosophila brain.

Endothelial progenitor cells: new perspectives and applications in cardiovascular therapies.

For over 10 years, bone marrow-derived endothelial progenitor cells (EPCs) have been studied as a novel biomarker to assess the severity of cardiovascular diseases, and as a potential new strategy in regenerative medicine. Cell-based therapy to stimulate postnatal vasculogenesis or to repair vascular integrity is being evaluated for cardiovascular diseases with excess morbidity and mortality, including ischemic heart disease, in-stent restenosis, pulmonary hypertension and peripheral arterial occlusive disease. Although clinical experience is still limited, observed effects appear modest compared with preclinical models.

Elongin B/C recruitment regulates substrate binding by CIS.

SOCS proteins play a major role in the regulation of cytokine signaling. They are recruited to activated receptors and can suppress signaling by different mechanisms including targeting of the receptor complex for proteasomal degradation. The activity of SOCS proteins is regulated at different levels including transcriptional control and posttranslational modification.

Lignin engineering.

Lignins are aromatic polymers that are present mainly in secondarily thickened plant cell walls. Several decades of research have elucidated the main biosynthetic routes toward the monolignols and demonstrated that lignin amounts can be engineered and that plants can cope with large shifts in p-hydroxyphenyl/guaiacyl/syringyl (H/G/S) lignin compositional ratios. It has also become clear that lignins incorporate many more units than the three monolignols described in biochemistry textbooks.

Altered expression of key dopaminergic regulatory proteins in the postnatal brain following perinatal n-3 fatty acid dietary deficiency.

The consequences of maternal linolenic acid (LNA, 18:3n-3) dietary deficiency on key dopamine (DA)-associated regulatory proteins in mesolimbic and mesocortical structures of the postnatal rat brain have been investigated. A marked (4.5-fold) decrease of the DA-synthesizing enzyme tyrosine hydroxylase accompanied by a down-regulation (approx 7.

Gene therapy for haemophilia "A" and "B": efficacy, safety and immune consequences.

The first successful gene therapy trials for the treatment of hereditary disorders underscore the potential of gene therapy to combat disease and alleviate human suffering. The development of gene therapy for haemophilia is not only a research priority in its own right but also serves as an ideal trailblazer for many different diseases. Significant progress has recently been made in the development of gene therapy for the treatment of haemophilia A and B.

Listeria comet tails: the actin-based motility machinery at work.

Listeria monocytogenes is a master of mimicry that uses the host cell actin system both to move within the cytoplasm of infected cells and for cell-to-cell spread. Recent studies of Listeria and similarly acting pathogens have generated leaps in our understanding of the actin-based force producing machinery. This machinery is essential for most motile properties of cells, not least for cell migration.