Project description:Molecular underpinnings of vertebrate retinal differentiation and maturation are poorly understood, particularly for non-mammalian species. We generated single-cell transcriptome data from the larval zebrafish retina and characterized gene expression diversity among photoreceptor subtypes and their progenitors.
Project description:Vertebrate vision is mediated by two kinds of photoreceptors, rods and cones, responsible for dim- and bright-light vision, respectively. Gene expression differences among cone subtypes remain poorly understood compared with rods. We generated single-cell transcriptome data using a droplet-based approach to reveal the extent of gene expression diversity among adult zebrafish photoreceptor subtypes. Populations of photoreceptor cells were enriched by using the transgenic zebrafish lines, Tg(rho:EGFP)ja2Tg and Tg(gnat2:EGFP)ja23Tg, which express GFP in rods and all cone subtypes, respectively. By analyzing the single-cell transcriptomes, we found that in addition to the four canonical zebrafish cone types (ultraviolet, blue, green and red), there exist subpopulations of green and red cones in the ventral retina that express red-shifted opsin paralogs (opn1mw4 and opn1lw1). This work lays a foundation for future studies aimed at understanding how molecular differences among cone subtypes affect photoreceptor function.
Project description:The Drosophila eye is a powerful model system to study the dynamics of cell differentiation, cell state transitions, cell maturation, and pattern formation. However, a high-resolution single cell genomics resource that accurately profiles all major cell types of the larval eye disc and their spatiotemporal relationships is lacking. Here, we report transcriptomic and chromatin accessibility data for all known cell types in the developing eye. Photoreceptors appear as strands of cells that represent dynamic developmental timelines. Photoreceptor subtypes are transcriptionally distinct when they begin to differentiate, but then appear to assume a common transcriptome as they mature. We identify novel cell type maturation genes, enhancers, and potential regulators, as well as genes with distinct R3 or R4 photoreceptor specific expression. Finally, we observe that photoreceptor chromatin accessibility is more permissive than non-neuronal lens-secreting cone cells, which show a more restrictive chromatin profile. These single cell genomics atlases will greatly enhance the power of the Drosophila eye as a model system.
Project description:The signaling molecule retinoic acid (RA) regulates rod and cone photoreceptor fate, differentiation, and survival. The purpose of this study was to identify eye-specific genes controlled by RA during photoreceptor differentiation in the zebrafish. 6 samples; 3 replicates of 2 conditions
Project description:Purpose: Avian photoreceptors are a diverse class of neurons, comprised of four single cones, the two members of the double cone, and rods. Many distinctive features of photoreceptor subtypes, including spectral tuning, oil droplet size and pigmentation, synaptic targets and spatial patterning, have been well characterized, but the molecular mechanisms underlying these attributes have not been explored. Furthermore, the signaling events and transcriptional regulators driving the differentiation of these diverse photoreceptors are currently unknown. Methods: To identify genes specifically expressed in distinct chicken (Gallus gallus) photoreceptor subtypes, we developed fluorescent reporters that label photoreceptor subpopulations, isolated these subpopulations using fluorescence-activated cell sorting, subjected them to next-generation sequencing, and conducted differential expression analysis. Results: We identified hundreds of differentially expressed genes from photoreceptor subpopulations labeled with rhodopsin, red opsin, green opsin, and violet opsin reporters. These genes are involved in a variety of processes, including phototransduction, transcriptional regulation, cell adhesion, maintenance of intra- and extra-cellular structure, and metabolism. Of particular note are a variety of differentially expressed transcription factors, which may drive and maintain photoreceptor diversity, and cell adhesion molecules that may mediate spatial patterning of photoreceptors and act to establish retinal circuitry. Conclusions: These analyses provide a framework for future studies that will dissect the role of these various factors in the differentiation of avian photoreceptor subtypes. mRNA expression profiling of 5 pairs of photoreceptor subtypes isolated from chicken retinal explants, 3 replicates per sample
Project description:The signaling molecule retinoic acid (RA) regulates rod and cone photoreceptor fate, differentiation, and survival. The purpose of this study was to identify eye-specific genes controlled by RA during photoreceptor differentiation in the zebrafish.
Project description:Innate Lymphoid cells (ILCs) are a group of tissue resident lymphocytes that participate in immune defense and tissue homeostasis. The existence and ontogeny of ILCs during zebrafish embryonic development are not defined. During embryogenesis, hematopoietic stem cells (HSCs) and HSC-independent Progenitor Cells (HPCs) form contemporaneously and produce overlapping and distinct immune cell types. To delineate when ILCs emerge and if they originate exclusively from HSCs or HPCs, we performed lineage tracing of the emerging hematopoietic system during larval development followed by single cell RNA sequencing of HSC and HPC progeny. To determine if the ILC-like cells are derived from the definitive hematopoietic wave, we did lineage tracing and scRNA-seq experiment in runx1W84X mutants and illustrated that all ILC-like clusters are Runx1-dependent. We confirmed that the transcriptionally detected larval ILC-like cells are Rag-independent and Il2rg-dependent. Lastly, embryonic ILCs are functional because they respond to an immune system stimulation with a viral mimic. The work provides fundamental knowledge on the early establishment of immune hierarchies and opens the zebrafish model to the exploration of ILC origination and function.
Project description:We report single-cell RNA sequencing of cells from the Tg(lck:GFP) larval zebrafish tail, to identify cell types expressing the marker and to identify gene candidates related to T cell migration behaviors. We identified 330 putative T cells and 131 putative epithelial cells. Differential expression analysis between the two groups revealed genes related to actin cytoskeleton remodeling associated with the T cells, in addition to canonical T and ubiquitous immune cell markers.