Biology subjects

Aghayeva, U.

Publications and source records attributed to Aghayeva, U..

3 recordsLinked to original sources

bioRxiv2020

DAF-16/FoxO and DAF-12/VDR control cellular plasticity both cell-autonomously and via interorgan signaling

Many cell types display the remarkable ability to alter their cellular phenotype in response to specific external or internal signals. Such phenotypic plasticity is apparent in the nematode C. elegans when adverse environmental conditions trigger entry into the dauer diapause stage. This entry is accompanied by structural, molecular and functional remodeling of a number of distinct tissue types of the animal, including its nervous system. The transcription factor effectors of three different hormonal signaling systems, the insulin-responsive DAF-16/FoxO transcription factor, the TGF{beta}-responsive DAF-3/SMAD transcription factor and the steroid nuclear hormone receptor, DAF-12/VDR, a homolog of the vitamin D receptor, were previously shown to be required for entering the dauer arrest stage, but their cellular and temporal focus of action for the underlying cellular remodeling processes remained incompletely understood. Through the generation of conditional alleles that allowed us to spatially and temporally control gene activity, we show here that all three transcription factors are not only required to initiate tissue remodeling upon entry into the dauer stage, as shown before, but are also continuously required to maintain the remodeled state. We show that DAF-3/SMAD is required in sensory neurons to promote and then maintain animal-wide tissue remodeling events. In contrast, DAF-16/FoxO or DAF-12/VDR act cell autonomously to control anatomical, molecular and behavioral remodeling events in specific cell types. Intriguingly, we also uncover non-cell autonomous function of DAF-16/FoxO and DAF-12/VDR in nervous system remodeling, indicating the presence of several insulin-dependent inter-organ signaling axes. Our findings provide novel perspectives on how hormonal systems control tissue remodeling.

genetics↗

bioRxiv2018

Plasticity of the electrical connectome of C. elegans

The patterns of electrical synapses of an animal nervous system (\"electrical connectome\"), as well as the functional properties and plasticity of electrical synapses, are defined by the neuron type-specific complement of electrical synapse constituents. We systematically examine here properties of the electrical connectome of the nematode C. elegans through a genome- and nervous system-wide analysis of the expression pattern of the central components of invertebrate electrical synapses, the innexins, revealing highly complex combinatorial patterns of innexin expression throughout the nervous system. We find that the complex expression patterns of 12 out of 14 neuronally expressed innexins change in a strikingly neuron type-specific manner throughout most of the nervous system, if animals encounter harsh environmental conditions and enter the dauer arrest stage. We systematically describe the plasticity of locomotory patterns of dauer stage animals and, by analyzing several individual electrical synapses, we demonstrate that dauer stage-specific electrical synapse remodeling is responsible for specific aspects of the altered locomotory patterns as well as altered chemosensory behavior of dauer stage animals. We describe an intersectional gene regulatory mechanism, involving terminal selector and FoxO transcription factors that are responsible for inducing innexin expression changes in a neuron type- and environment-specific manner. Taken together, our studies illustrate the remarkably dynamic nature of electrical synapses on a nervous system-wide level and describe regulatory strategies for how these alterations are achieved.

neuroscience↗

bioRxiv2017

An atlas of Caenorhabditis elegans chemoreceptor expression

One goal of modern day neuroscience is the establishment of molecular maps that assign unique features to individual neuron types. Such maps provide important starting points for neuron classification, for functional analysis and for developmental studies aimed at defining the molecular mechanisms of neuron identity acquisition and neuron identity diversification. In this resource paper, we describe a nervous system-wide map of the potential expression sites of 244 members of the largest gene family in the C. elegans genome, rhodopsin-like (class A) GPCR chemoreceptors, using classic gfp reporter gene technology. We cover representatives of all sequence families of chemoreceptors GPCRs, some of which were previously entirely uncharacterized. Most reporters are expressed in a very restricted number of cells, often just in single cells. We assign GPCR reporter expression to all but two of the 37 sensory neuron classes of the sex-shared, core nervous system. Some sensory neurons express a very small number of receptors, while others, particularly nociceptive neurons, co-express several dozen GPCR reporter genes. GPCR reporters are also expressed in a wide range of inter- and motorneurons, as well as nonneuronal cells, suggesting that GPCRs may constitute receptors not just for environmental signals, but also for internal cues. We observe only one notable, frequent association of coexpression patterns, namely in one nociceptive amphid (ASH) and two nociceptive phasmid sensory neurons (PHA, PHB). We identified GPCRs with sexually dimorphic expression and several GPCR reporters that are expressed in a left/right asymmetric manner. We identified a substantial degree of GPCR expression plasticity; particularly in the context of the environmentally-induced dauer diapause stage when one third of all tested GPCRs alter the cellular specificity of their expression within and outside the nervous system. Intriguingly, in a number of cases, the dauer-specific alterations of GPCR reporter expression in specific neuron classes are maintained during postdauer life and in some case new patterns are induced post-dauer, demonstrating that GPCR gene expression may serve as traits of life history. Taken together, our resource provides an entry point for functional studies and also offers a host of molecular markers for studying molecular patterning and plasticity of the nervous system.\n\nAUTHOR SUMMARYMaps of gene expression patterns in the nervous system provide an important resource for neuron classification, for functional analysis and for developmental studies that ask how different neurons acquire their unique identities. By analyzing transgenic gfp reporter strains, we describe here the expression pattern of 244 putative chemosensory receptor-encoding genes, which constitute the largest gene family in C.elegans. We show that, as expected, chemoreceptor expression is enriched in chemosensory neurons but it is also expressed in a wide range of interneurons, motorneurons, as well as non-neuronal cells, suggesting that putative chemosensory receptors may not just sense environmental signals but also internal cues. We find that each chemoreceptor is expressed in a few neuron types, often just one, but each neuron type can express a large number of chemoreceptors. Interestingly, we uncovered that chemoreceptor expression is remarkably plastic, particularly in the context of the environmentally-induced dauer diapause stage. Taken together, this molecular atlas of chemosensory receptors provides an entry point for functional studies and offers a host of markers for studying neuronal patterning and plasticity.

genetics↗