Autophagy mediates phosphatidylserine exposure and phagosome degradation during apoptosis through specific functions of GABARAP/LGG-1 and LC3/LGG-2.

Phagocytosis and macroautophagy/autophagy are 2 processes involved in lysosome-mediated clearance of extracellular and intracellular components, respectively. Recent studies have identified the recruitment of the autophagic protein LC3 during phagocytosis of apoptotic corpses in what is now called LC3-associated phagocytosis (LAP). LAP is a distinct process from autophagy but it relies on some members of the autophagy pathway to allow efficient degradation of the phagocytosed cargo.

Tools and methods to analyze autophagy in C. elegans.

For a long time, autophagy has been mainly studied in yeast or mammalian cell lines, and assays for analyzing autophagy in these models have been well described. More recently, the involvement of autophagy in various physiological functions has been investigated in multicellular organisms. Modification of autophagy flux is involved in developmental processes, resistance to stress conditions, aging, cell death and multiple pathologies.

Coe genes are expressed in differentiating neurons in the central nervous system of protostomes.

Genes of the coe (collier/olfactory/early B-cell factor) family encode Helix-Loop-Helix transcription factors that are widely conserved in metazoans and involved in many developmental processes, neurogenesis in particular. Whereas their functions during vertebrate neural tube formation have been well documented, very little is known about their expression and role during central nervous system (CNS) development in protostomes. Here we characterized the CNS expression of coe genes in the insect Drosophila melanogaster and the polychaete annelid Platynereis dumerilii, which belong to different subgroups of protostomes and show strikingly different modes of development.

Orthologs of key vertebrate neural genes are expressed during neurogenesis in the annelid Platynereis dumerilii.

The molecular mechanisms underlying the formation and patterning of the nervous system are relatively poorly understood for lophotrochozoans (like annelids) as compared with ecdysozoans (especially Drosophila) and deuterostomes (especially vertebrates). Therefore, we have undertaken a candidate gene approach to study aspects of neurogenesis in a polychaete annelid Platynereis dumerilii. We determined the spatiotemporal expression for Platynereis orthologs of four genes (SoxB, Churchill, prospero/Prox, and SoxC) known to play key roles in vertebrate neurogenesis.

Sponge genes provide new insight into the evolutionary origin of the neurogenic circuit.

The nerve cell is a eumetazoan (cnidarians and bilaterians) synapomorphy [1]; this cell type is absent in sponges, a more ancient phyletic lineage. Here, we demonstrate that despite lacking neurons, the sponge Amphimedon queenslandica expresses the Notch-Delta signaling system and a proneural basic helix loop helix (bHLH) gene in a manner that resembles the conserved molecular mechanisms of primary neurogenesis in bilaterians. During Amphimedon development, a field of subepithelial cells expresses the Notch receptor, its ligand Delta, and a sponge bHLH gene, AmqbHLH1.

atonal- and achaete-scute-related genes in the annelid Platynereis dumerilii: insights into the evolution of neural basic-Helix-Loop-Helix genes.

Background: Functional studies in model organisms, such as vertebrates and Drosophila, have shown that basic Helix-loop-Helix (bHLH) proteins have important roles in different steps of neurogenesis, from the acquisition of neural fate to the differentiation into specific neural cell types. However, these studies highlighted many differences in the expression and function of orthologous bHLH proteins during neural development between vertebrates and Drosophila. To understand how the functions of neural bHLH genes have evolved among bilaterians, we have performed a detailed study of bHLH genes during nervous system development in the polychaete annelid, Platynereis dumerilii, an organism which is evolutionary distant from both Drosophila and vertebrates.

Origin and diversification of the basic helix-loop-helix gene family in metazoans: insights from comparative genomics.

Background: Molecular and genetic analyses conducted in model organisms such as Drosophila and vertebrates, have provided a wealth of information about how networks of transcription factors control the proper development of these species. Much less is known, however, about the evolutionary origin of these elaborated networks and their large-scale evolution. Here we report the first evolutionary analysis of a whole superfamily of transcription factors, the basic helix-loop-helix (bHLH) proteins, at the scale of the whole metazoan kingdom.

The Drosophila RNA-binding protein ELAV is required for commissural axon midline crossing via control of commissureless mRNA expression in neurons.

Drosophila ELAV is the founding member of an evolutionarily conserved family of RNA-binding proteins considered as key inducers of neuronal differentiation. Although several ELAV-specific targets have been identified, little is known about the role of elav during neural development. Here, we report a detailed characterization of the elav mutant commissural phenotype.