scholarly journals A gene expression atlas of abicoid-depleted Drosophila embryo reveals early canalization of cell fate

2014 ◽  
Author(s):  
Max V Staller ◽  
Charless C Fowlkes ◽  
Meghan D.J. Bragdon ◽  
Zeba B. Wunderlich ◽  
Angela DePace
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Early Stage ◽  
Expression Patterns ◽  
Drosophila Embryo ◽  
Wild Type ◽  
Cell Fates ◽  
Gene Expression Atlas ◽  
Expression Atlas ◽  
Gene Regulatory

In developing embryos, gene regulatory networks canalize cells towards discrete terminal fates. We studied the behavior of the anterior-posterior segmentation network in Drosophila melanogaster embryos depleted of a key maternal input, bicoid (bcd), by building a cellular- resolution gene expression atlas containing measurements of 12 core patterning genes over 6 time points in early development. With this atlas, we determine the precise perturbation each cell experiences, relative to wild type, and observe how these cells assume cell fates in the perturbed embryo. The first zygotic layer of the network, consisting of the gap and terminal genes, is highly robust to perturbation: all combinations of transcription factor expression found in bcd depleted embryos were also found in wild type embryos, suggesting that no new cell fates were created even at this very early stage. All of the gap gene expression patterns in the trunk expand by different amounts, a feature that we were unable to explain using two simple models of the effect of bcd depletion. In the second layer of the network, depletion of bcd led to an excess of cells expressing both even skipped and fushi tarazu early in the blastoderm stage, but by gastrulation this overlap resolved into mutually exclusive stripes. Thus, following depletion of bcd, individual cells rapidly canalize towards normal cell fates in both layers of this gene regulatory network. Our gene expression atlas provides a high resolution picture of a classic perturbation and will enable further modeling of canalization in this transcriptional network.

scholarly journals A gene expression atlas of a bicoid-depleted Drosophila embryo reveals early canalization of cell fate

Development ◽  
2015 ◽  
Vol 142 (3) ◽  
pp. 587-596 ◽  
Author(s):  
M. V. Staller ◽  
C. C. Fowlkes ◽  
M. D. J. Bragdon ◽  
Z. Wunderlich ◽  
J. Estrada ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Drosophila Embryo ◽  
Gene Expression Atlas ◽  
Expression Atlas

scholarly journals A comprehensive RNA-Seq-based gene expression atlas of the summer squash (Cucurbita pepo) provides insights into fruit morphology and ripening mechanisms

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Aliki Xanthopoulou ◽  
Javier Montero-Pau ◽  
Belén Picó ◽  
Panagiotis Boumpas ◽  
Eleni Tsaliki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cucurbita Pepo ◽  
Developmental Stages ◽  
Lateral Roots ◽  
Expression Patterns ◽  
Male Flower ◽  
Differentially Expressed ◽  
Gene Expression Atlas ◽  
Summer Squash ◽  
Expression Atlas

Abstract Background Summer squash (Cucurbita pepo: Cucurbitaceae) are a popular horticultural crop for which there is insufficient genomic and transcriptomic information. Gene expression atlases are crucial for the identification of genes expressed in different tissues at various plant developmental stages. Here, we present the first comprehensive gene expression atlas for a summer squash cultivar, including transcripts obtained from seeds, shoots, leaf stem, young and developed leaves, male and female flowers, fruits of seven developmental stages, as well as primary and lateral roots. Results In total, 27,868 genes and 2352 novel transcripts were annotated from these 16 tissues, with over 18,000 genes common to all tissue groups. Of these, 3812 were identified as housekeeping genes, half of which assigned to known gene ontologies. Flowers, seeds, and young fruits had the largest number of specific genes, whilst intermediate-age fruits the fewest. There also were genes that were differentially expressed in the various tissues, the male flower being the tissue with the most differentially expressed genes in pair-wise comparisons with the remaining tissues, and the leaf stem the least. The largest expression change during fruit development was early on, from female flower to fruit two days after pollination. A weighted correlation network analysis performed on the global gene expression dataset assigned 25,413 genes to 24 coexpression groups, and some of these groups exhibited strong tissue specificity. Conclusions These findings enrich our understanding about the transcriptomic events associated with summer squash development and ripening. This comprehensive gene expression atlas is expected not only to provide a global view of gene expression patterns in all major tissues in C. pepo but to also serve as a valuable resource for functional genomics and gene discovery in Cucurbitaceae.

scholarly journals Duplication of spiralian-specific TALE genes and evolution of the blastomere specification mechanism in the bivalve lineage

EvoDevo ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Supanat Phuangphong ◽  
Jumpei Tsunoda ◽  
Hiroshi Wada ◽  
Yoshiaki Morino
Keyword(s):  
Cell Fate ◽  
Early Development ◽  
Expression Patterns ◽  
Cell Fate Specification ◽  
Fate Map ◽  
Cell Fates ◽  
Cell Specification ◽  
Cytoplasmic Content ◽  
Gene Regulatory ◽  
Unique Cell

Abstract Background Despite the conserved pattern of the cell-fate map among spiralians, bivalves display several modified characteristics during their early development, including early specification of the D blastomere by the cytoplasmic content, as well as the distinctive fate of the 2d blastomere. However, it is unclear what changes in gene regulatory mechanisms led to such changes in cell specification patterns. Spiralian-TALE (SPILE) genes are a group of spiralian-specific transcription factors that play a role in specifying blastomere cell fates during early development in limpets. We hypothesised that the expansion of SPILE gene repertoires influenced the evolution of the specification pattern of blastomere cell fates. Results We performed a transcriptome analysis of early development in the purplish bifurcate mussel and identified 13 SPILE genes. Phylogenetic analysis of the SPILE gene in molluscs suggested that duplications of SPILE genes occurred in the bivalve lineage. We examined the expression patterns of the SPILE gene in mussels and found that some SPILE genes were expressed in quartet-specific patterns, as observed in limpets. Furthermore, we found that several SPILE genes that had undergone gene duplication were specifically expressed in the D quadrant, C and D quadrants or the 2d blastomere. These expression patterns were distinct from the expression patterns of SPILE in their limpet counterparts. Conclusions These results suggest that, in addition to their ancestral role in quartet specification, certain SPILE genes in mussels contribute to the specification of the C and D quadrants. We suggest that the expansion of SPILE genes in the bivalve lineage contributed to the evolution of a unique cell fate specification pattern in bivalves.

scholarly journals A 3D gene expression atlas of the floral meristem based on spatial reconstruction of single nucleus RNA sequencing data

2021 ◽  
Author(s):  
Manuel Neumann ◽  
Xiaocai Xu ◽  
Cezary Smaczniak ◽  
Julia Schumacher ◽  
Wenhao Yan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Expression Patterns ◽  
Floral Meristem ◽  
Cellular Heterogeneity ◽  
Sequencing Data ◽  
Gene Expression Atlas ◽  
Spatial Reconstruction ◽  
Expression Atlas ◽  
3D Gene

Identity and functions of plant cells are influenced by their precise cellular location within the plant body. Cellular heterogeneity in growth and differentiation trajectories results in organ patterning. Therefore, assessing this heterogeneity at molecular scale is a major question in developmental biology. Single-cell transcriptomics (scRNA-seq) allows to characterize and quantify gene expression heterogeneity in developing organs at unprecedented resolution. However, the original physical location of the cell is lost during the scRNA-seq procedure. To recover the original location of cells is essential to link gene activity with cellular function and morphology. Here, we reconstruct genome-wide gene expression patterns of individual cells in a floral meristem by combining single-nuclei RNA-seq with 3D spatial reconstruction. By this, gene expression differences among meristematic domains giving rise to different tissue and organ types can be determined. As a proof of principle, the data are used to trace the initiation of vascular identity within the floral meristem. Our work demonstrates the power of spatially reconstructed single cell transcriptome atlases to understand plant morphogenesis. The floral meristem 3D gene expression atlas can be accessed at http://threed-flower-meristem.herokuapp.com

scholarly journals Precision of Tissue Patterning is Controlled by Dynamical Properties of Gene Regulatory Networks

2019 ◽  
Author(s):  
Katherine Exelby ◽  
Edgar Herrera-Delgado ◽  
Lorena Garcia Perez ◽  
Ruben Perez-Carrasco ◽  
Andreas Sagner ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulatory Networks ◽  
Regulatory Network ◽  
Regulatory Networks ◽  
Expression Patterns ◽  
Cell Fates ◽  
Gene Circuits ◽  
Stochastic Fluctuations ◽  
Network Properties ◽  
Gene Regulatory

AbstractDuring development, gene regulatory networks allocate cell fates by partitioning tissues into spatially organised domains of gene expression. How the sharp boundaries that delineate these gene expression patterns arise, despite the stochasticity associated with gene regulation, is poorly understood. We show, in the vertebrate neural tube, using perturbations of coding and regulatory regions, that the structure of the regulatory network contributes to boundary precision. This is achieved, not by reducing noise in individual genes, but by the configuration of the network modulating the ability of stochastic fluctuations to initiate gene expression changes. We use a computational screen to identify network properties that influence boundary precision, revealing two dynamical mechanisms by which small gene circuits attenuate the effect of noise in order to increase patterning precision. These results highlight design principles of gene regulatory networks that produce precise patterns of gene expression.

scholarly journals A chelicerate Wnt gene expression atlas: novel insights into the complexity of arthropod Wnt-patterning

EvoDevo ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ralf Janssen ◽  
Matthias Pechmann ◽  
Natascha Turetzek
Keyword(s):  
Gene Expression ◽  
Expression Patterns ◽  
Large Family ◽  
Animal Evolution ◽  
Gene Expression Atlas ◽  
Outgroup Species ◽  
Expression Atlas ◽  
Duplication Events ◽  
Complete Set ◽  
High Degree

AbstractThe Wnt genes represent a large family of secreted glycoprotein ligands that date back to early animal evolution. Multiple duplication events generated a set of 13 Wnt families of which 12 are preserved in protostomes. Embryonic Wnt expression patterns (Wnt-patterning) are complex, representing the plentitude of functions these genes play during development. Here, we comprehensively investigated the embryonic expression patterns of Wnt genes from three species of spiders covering both main groups of true spiders, Haplogynae and Entelegynae, a mygalomorph species (tarantula), as well as a distantly related chelicerate outgroup species, the harvestman Phalangium opilio. All spiders possess the same ten classes of Wnt genes, but retained partially different sets of duplicated Wnt genes after whole genome duplication, some of which representing impressive examples of sub- and neo-functionalization. The harvestman, however, possesses a more complete set of 11 Wnt genes but with no duplicates. Our comprehensive data-analysis suggests a high degree of complexity and evolutionary flexibility of Wnt-patterning likely providing a firm network of mutational protection. We discuss the new data on Wnt gene expression in terms of their potential function in segmentation, posterior elongation, and appendage development and critically review previous research on these topics. We conclude that earlier research may have suffered from the absence of comprehensive gene expression data leading to partial misconceptions about the roles of Wnt genes in development and evolution.

scholarly journals Sequence-based model of gap gene regulatory network

2015 ◽  
Author(s):  
Konstantin N Kozlov ◽  
Vitaly V Gursky ◽  
Ivan V Kulakovskiy ◽  
Maria G Samsonova
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Binding Sites ◽  
Gene Network ◽  
Expression Patterns ◽  
Gene Expression Patterns ◽  
Model Output ◽  
Wild Type ◽  
Gap Gene ◽  
Gene Regulatory

Background: The detailed analysis of transcriptional regulation is crucially important for understanding biological processes. The gap gene network in Drosophila attracts large interest among researches studying mechanisms of transcriptional regulation. It implements the most upstream regulatory layer of the segmentation gene network. The knowledge of molecular mechanisms involved in gap gene regulation is far less complete than that of genetics of the system. Mathematical modeling goes beyond insights gained by genetics and molecular approaches. It allows us to reconstruct wild-type gene expression patterns in silico, infer underlying regulatory mechanism and prove its sufficiency. Results: We developed a new model that provides a dynamical description of gap gene regulatory systems, using detailed DNA-based information, as well as spatial transcription factor concentration data at varying time points. We showed that this model correctly reproduces gap gene expression patterns in wild type embryos and is able to predict gap expression patterns in Kr mutants and four reporter constructs. We used four-fold cross validation test and fitting to random dataset to validate the model and proof its sufficiency in data description. The identifiability analysis showed that most model parameters are well identifiable. We reconstructed the gap gene network topology and studied the impact of individual transcription factor binding sites on the model output. We measured this impact by calculating the site regulatory weight as a normalized difference between the residual sum of squares error for the set of all annotated sites and the set, from which the site of interest was left out. Conclusions: The reconstructed topology of the gap gene network is in agreement with previous modeling results and data from literature. We showed that 1) the regulatory weights of transcription factor binding sites show very weak correlation with their PWM score; 2) sites with low regulatory weight are important for the model output; 3) functional important sites are not exclusively located in cis-regulatory elements, but are rather dispersed through regulatory region. It is of importance that some of the sites with high functional impact in hb, Kr and kni regulatory regions coincide with strong sites annotated and verified in Dnase I footprint assays. Keywords: transcription; thermodynamics; reaction-diffusion; drosophila

scholarly journals Duplication of Spiralian-Specific TALE Genes And Evolution of The Blastomere Specification Mechanism In The Bivalve Lineage

2021 ◽  
Author(s):  
Supanat Phuangphong ◽  
Jumpei Tsunoda ◽  
Hiroshi Wada ◽  
Yoshiaki Morino
Keyword(s):  
Cell Fate ◽  
Early Development ◽  
Functional Divergence ◽  
Expression Patterns ◽  
Fate Map ◽  
Cell Fates ◽  
Cell Specification ◽  
Cytoplasmic Content ◽  
Gene Regulatory ◽  
Unique Cell

Abstract Background Despite the conserved pattern of the cell-fate map among spiralians, bivalves display several modified characteristics during their early development, including early specification of the D blastomere by the cytoplasmic content, as well as the distinctive fate of the 2d blastomere. However, it is unclear what changes in gene regulatory mechanisms led to such changes in cell specification patterns. Spiralian-TALE (SPILE) genes are a group of spiralian-specific transcription factors that play a role in specifying blastomere cell fates during early development in limpets. We hypothesised that the expansion of SPILE gene repertoires influenced the evolution of the specification pattern of blastomere cell fates.Results We performed a transcriptome analysis of early development in the purplish bifurcate mussel and identified 13 SPILE genes. Phylogenetic analysis of the SPILE gene in bivalves and limpets suggested that extra duplications of SPILE genes occurred in the bivalve lineage. We examined the expression patterns of the SPILE gene in mussels and found that some SPILE genes were expressed in quartet-specific patterns, as observed in limpets. Furthermore, we found that several SPILE genes that had undergone gene duplication were specifically expressed in the D quadrant, C and D quadrants or the 2d blastomere. These expression patterns were distinct from the expression patterns of SPILE in their limpet counterparts. Conclusions These results suggest that, in addition to their ancestral role in quartet specification, bivalve SPILE genes contributed to the specification of C and D quadrants. We propose that the expansion of SPILE genes in the bivalve lineage created extra SPILE genes that underwent expression pattern and functional divergence, thereby resulting in the evolution of a unique cell-fate specification pattern in bivalves.

scholarly journals Precision of tissue patterning is controlled by dynamical properties of gene regulatory networks

Development ◽  
2021 ◽  
Vol 148 (4) ◽  
pp. dev197566
Author(s):  
Katherine Exelby ◽  
Edgar Herrera-Delgado ◽  
Lorena Garcia Perez ◽  
Ruben Perez-Carrasco ◽  
Andreas Sagner ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Regulatory Networks ◽  
Regulatory Network ◽  
Regulatory Networks ◽  
Expression Patterns ◽  
Cell Fates ◽  
Gene Circuits ◽  
Stochastic Fluctuations ◽  
Network Properties ◽  
Gene Regulatory

ABSTRACTDuring development, gene regulatory networks allocate cell fates by partitioning tissues into spatially organised domains of gene expression. How the sharp boundaries that delineate these gene expression patterns arise, despite the stochasticity associated with gene regulation, is poorly understood. We show, in the vertebrate neural tube, using perturbations of coding and regulatory regions, that the structure of the regulatory network contributes to boundary precision. This is achieved, not by reducing noise in individual genes, but by the configuration of the network modulating the ability of stochastic fluctuations to initiate gene expression changes. We use a computational screen to identify network properties that influence boundary precision, revealing two dynamical mechanisms by which small gene circuits attenuate the effect of noise in order to increase patterning precision. These results highlight design principles of gene regulatory networks that produce precise patterns of gene expression.

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