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Drosophila melanogaster females have two X chromosomes and two autosome sets (XX;AA), while males have a single X chromosome and two autosome sets (X;AA). Drosophila male somatic cells...
Vertebrate neural crest cells are multipotent and differentiate into structures that include cartilage and the bones of the face, as well as much of the peripheral nervous system. Understanding how different m...
Development of the eye depends partly on the periocular mesenchyme derived from the neural crest (NC), but the fate of NC cells in mammalian eye development and the signals coordinating the formation of ocular...
During the translation of mRNA into polypeptide, elongation factor G (EF-G) catalyzes the translocation of peptidyl-tRNA from the A site to the P site of the ribosome. According to the 'classical' model, EF-G ...
Translocation of peptidyl-tRNA and mRNA within the ribosome during protein synthesis is promoted by the elongation factor EF-G and by the hydrolysis of GTP. A new study reports that EF-G binds to ribosomes as ...
Information from careful measurements of the affinity of ribosome-associated proteins for GTP and GDP, and from structural analyses, suggests that elongation factor-G must assume three different structures dur...
An analysis of an integrated network of over 150,000 functional and physical interactions in yeast suggests that the network can be hierarchically decomposed into themes and thematic maps. This decomposition c...
Large-scale studies have revealed networks of various biological interaction types, such as protein-protein interaction, genetic interaction, transcriptional regulation, sequence homology, and expression corre...
Analysis of a yeast network that integrates five interaction datasets reveals the presence of large topological structures reflecting biological themes.
The phosphoprotein Dishevelled (Dsh) is an essential component of Wnt signaling pathways and transduces signals into three separate branches, the canonical, non-canonical and Ca2+ pathways. How Dsh focuses signal...
Structure-function analysis of the Dishevelled (Dsh) protein in frog embryos has defined sequences that regulate Dsh nuclear localization, which proves critical for Wnt signaling.
Dishevelled (Dsh) is a key component of multiple signaling pathways that are initiated by Wnt secreted ligands and Frizzled receptors during embryonic development. Although Dsh has been detected in a number of...
It is widely supposed that the tissue specificity of gene expression indicates gene function. Now, an extensive analysis of gene expression in the mouse reveals that quantitative measurement of expression leve...
Large-scale quantitative analysis of transcriptional co-expression has been used to dissect regulatory networks and to predict the functions of new genes discovered by genome sequencing in model organisms such...
Large-scale microarray analyses reveal that transcriptional co-regulation patterns can be remarkably helpful in predicting the function of novel mouse genes.
Centromere function is remarkably conserved between species, yet the satellite sequences that make up centromeric DNA are highly divergent. Proteins that bind these sequences appear to be evolving under positi...
Analysis of knockout mice has brought into question the previously proposed role of the phosphatidylserine receptor (Ptdsr) in the clearance of apoptotic cell corpses, and has suggested important functions in ...
Phosphatidylserine on the dying cell surface helps identify apoptotic cells to phagocytes, which then engulf them. A candidate phagocyte receptor for phosphatidylserine was identified using phage display, but ...
Centromeres represent the last frontiers of plant and animal genomics. Although they perform a conserved function in chromosome segregation, centromeres are typically composed of repetitive satellite sequences...
Comparative analysis of the proteins that bind exclusively at the centromere provides evidence of an evolutionary battle that may make sense of sex.
Phagocytosis of apoptotic cells is fundamental to animal development, immune function and cellular homeostasis. The phosphatidylserine receptor (Ptdsr) on phagocytes has been implicated in the recognition and ...
Constitutive activation of the Wnt signaling pathway during lung development in mouse embryos causes some cells to develop a gut-like phenotype. These findings are reminiscent of classical embryological experi...
Studies in many model systems have shown that canonical signaling through the pathway downstream of ligands of the Wnt family can regulate multiple steps in organogenesis, including cell proliferation, differe...
The phenomenon of metaplasia, in which one tissue type is converted into another, is beginning to be explained in molecular terms. The transformation of lung to intestinal tissue has not previously been descri...
Drafting in cetaceans is defined as the transfer of forces between individuals without actual physical contact between them. This behavior has long been surmised to explain how young dolphin calves keep up wit...
Swimming animals set the water around them moving, and flying animals generate air movements. Other animals traveling with them can save energy by exploiting these movements of the fluid medium; similarly, a c...
A combination of mathematical modeling and direct observation of the swimming behavior of dolphin mother-calf pairs has shown how the calf can gain much of the energy required for swimming if it is positioned ...
Budding through the host-cell membrane is a key step in the life cycle of many viruses. Recent studies of retrovirus replication implicate a large number of cellular proteins in this process.
A retroviral Gag protein interacts with a cellular protein involved in forming endocytic vesicles in a manner that affects the production of virus particles. These findings help define the suite of host-cell c...
The retroviral Gag protein is the central player in the process of virion assembly at the plasma membrane, and is sufficient to induce the formation and release of virus-like particles. Recent evidence suggest...
A large-scale screen in Drosophila cells has shown how RNA interference can provide insights into the pathways controlling cell morphology.
The tumor suppressor gene product LKB1 has been identified as the upstream activating kinase for the stress-responsive AMP-activated kinase, providing a link between regulators of cellular metabolism and cell ...
The tumor suppressor kinase LKB1 has been identified as a physiologic activator of the key metabolic regulator 5'-AMP-activated protein kinase, establishing a possible molecular link between the regulation of ...
The diversity of metazoan cell shapes is influenced by the dynamic cytoskeletal network. With the advent of RNA-interference (RNAi) technology, it is now possible to screen systematically for genes controlling...
Several new studies have used RNA interference to screen for protein functions affecting cell shape, mitosis and cytokinesis of Drosophila cells in culture. One broad survey of nearly 1,000 proteins and three stu...
The AMP-activated protein kinase (AMPK) cascade is a sensor of cellular energy charge that acts as a 'metabolic master switch' and inhibits cell proliferation. Activation requires phosphorylation of Thr172 of ...
Functional genomic screening for new components of the signaling pathway that is triggered when T cells are activated has identified novel signaling molecules that are potential drug targets.
The activation of T cells, mediated by the T-cell receptor (TCR), activates a battery of specific membrane-associated, cytosolic and nuclear proteins. Identifying the signaling proteins downstream of TCR activ...
The insulin signaling pathway regulates organismal growth in response to nutrient conditions by controlling a range of metabolic and biosynthetic processes. Recent studies in Drosophila have shown how transcripti...
Studies in Drosophila have revealed the Forkhead-family transcription factor FOXO to be a crucial mediator of the branch of the insulin-signaling pathway that controls cell number.
Forkhead transcription factors belonging to the FOXO subfamily are negatively regulated by protein kinase B (PKB) in response to signaling by insulin and insulin-like growth factor in Caenorhabditis elegans and m...
Despite the widespread view that the effects of mutations are exacerbated by environmental stresses, some stresses have been found to alleviate the effects of mutations in bacteria.
Mutations are the ultimate fuel for evolution, but most mutations have a negative effect on fitness. It has been widely accepted that these deleterious fitness effects are, on average, magnified in stressful e...
The strategy of using 'phylogenetic footprinting' to find regulatory sites that are conserved between pairs of related complex genomes has led to the development of a suite of computational tools that succeed ...
Phylogenetic footprinting is an approach to finding functionally important sequences in the genome that relies on detecting their high degrees of conservation across different species. A new study shows how mu...
Fundamental questions in evolutionary genetics, including the possible advantage of sexual reproduction, depend critically on the effects of deleterious mutations on fitness. Limited existing experimental evid...