scholarly journals hox gene expression predicts tetrapod-like axial regionalization in the skate, Leucoraja erinacea

2021 ◽  
Vol 118 (51) ◽  
pp. e2114563118
Author(s):  
Katharine E. Criswell ◽  
Lucy E. Roberts ◽  
Eve T. Koo ◽  
Jason J. Head ◽  
J. Andrew Gillis
Keyword(s):  
Gene Expression ◽  
Vertebral Column ◽  
Evolutionary History ◽  
Cell Lineage ◽  
Axial Skeleton ◽  
Lineage Tracing ◽  
Paraxial Mesoderm ◽  
Evolutionary Transition ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis

The axial skeleton of tetrapods is organized into distinct anteroposterior regions of the vertebral column (cervical, trunk, sacral, and caudal), and transitions between these regions are determined by colinear anterior expression boundaries of Hox5/6, -9, -10, and -11 paralogy group genes within embryonic paraxial mesoderm. Fishes, conversely, exhibit little in the way of discrete axial regionalization, and this has led to scenarios of an origin of Hox-mediated axial skeletal complexity with the evolutionary transition to land in tetrapods. Here, combining geometric morphometric analysis of vertebral column morphology with cell lineage tracing of hox gene expression boundaries in developing embryos, we recover evidence of at least five distinct regions in the vertebral skeleton of a cartilaginous fish, the little skate (Leucoraja erinacea). We find that skate embryos exhibit tetrapod-like anteroposterior nesting of hox gene expression in their paraxial mesoderm, and we show that anterior expression boundaries of hox5/6, hox9, hox10, and hox11 paralogy group genes predict regional transitions in the differentiated skate axial skeleton. Our findings suggest that hox-based axial skeletal regionalization did not originate with tetrapods but rather has a much deeper evolutionary history than was previously appreciated.

scholarly journals Embryonic origin of the gnathostome vertebral skeleton

2017 ◽  
Vol 284 (1867) ◽  
pp. 20172121 ◽  
Author(s):  
Katharine E. Criswell ◽  
Michael I. Coates ◽  
J. Andrew Gillis
Keyword(s):  
Vertebral Column ◽  
Bone Matrix ◽  
Cell Lineage ◽  
Body Plan ◽  
Cartilaginous Fish ◽  
Lineage Tracing ◽  
Paraxial Mesoderm ◽  
Teleost Fishes ◽  
Embryonic Origin

The vertebral column is a key component of the jawed vertebrate (gnathostome) body plan, but the primitive embryonic origin of this skeleton remains unclear. In tetrapods, all vertebral components (neural arches, haemal arches and centra) derive from paraxial mesoderm (somites). However, in teleost fishes, vertebrae have a dual embryonic origin, with arches derived from somites, but centra formed, in part, by secretion of bone matrix from the notochord. Here, we test the embryonic origin of the vertebral skeleton in a cartilaginous fish (the skate, Leucoraja erinacea ) which serves as an outgroup to tetrapods and teleosts. We demonstrate, by cell lineage tracing, that both arches and centra are somite-derived. We find no evidence of cellular or matrix contribution from the notochord to the skate vertebral skeleton. These findings indicate that the earliest gnathostome vertebral skeleton was exclusively of somitic origin, with a notochord contribution arising secondarily in teleosts.

scholarly journals A High-Fidelity Cell Lineage Tracing Method for Obtaining Systematic Spatiotemporal Gene Expression Patterns inCaenorhabditis elegans

2013 ◽  
Vol 3 (5) ◽  
pp. 851-863 ◽  
Author(s):  
Daniel L Mace ◽  
Peter Weisdepp ◽  
Louis Gevirtzman ◽  
Thomas Boyle ◽  
Robert H Waterston
Keyword(s):  
Gene Expression ◽  
Expression Patterns ◽  
Cell Lineage ◽  
Lineage Tracing ◽  
Gene Expression Patterns ◽  
High Fidelity ◽  
Tracing Method

scholarly journals Molecular and Mechanical Cues for Somite Periodicity

2021 ◽  
Vol 9 ◽  
Author(s):  
Marta Linde-Medina ◽  
Theodoor H. Smit
Keyword(s):  
Gene Expression ◽  
Gene Regulatory Network ◽  
Regulatory Network ◽  
Vertebral Column ◽  
Mechanical Strain ◽  
Paraxial Mesoderm ◽  
Alternative View ◽  
Striped Pattern ◽  
Gene Regulatory

Somitogenesis refers to the segmentation of the paraxial mesoderm, a tissue located on the back of the embryo, into regularly spaced and sized pieces, i.e., the somites. This periodicity is important to assure, for example, the formation of a functional vertebral column. Prevailing models of somitogenesis are based on the existence of a gene regulatory network capable of generating a striped pattern of gene expression, which is subsequently translated into periodic tissue boundaries. An alternative view is that the pre-pattern that guides somitogenesis is not chemical, but of a mechanical origin. A striped pattern of mechanical strain can be formed in physically connected tissues expanding at different rates, as it occurs in the embryo. Here we argue that both molecular and mechanical cues could drive somite periodicity and suggest how they could be integrated.

scholarly journals New insights into the earlier evolutionary history of epiphytic macrolichens

2021 ◽  
Author(s):  
Qiuxia Yang ◽  
Yanyan Wang ◽  
Robert Lucking ◽  
H. Thorsten Lumbsch ◽  
Xin Wang ◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Evolutionary History ◽  
Terrestrial Ecosystems ◽  
Molecular Dating ◽  
Geometric Morphometric ◽  
New Family ◽  
Family Level ◽  
History Of ◽  
New Material ◽  
Geometric Morphometric Analysis

Lichens are well known as pioneer organisms colonizing bare surfaces such as rocks and therefore have been hypothesized to play a role in the early formation of terrestrial ecosystems. Given the rarity of fossil evidence, our understanding of the evolutionary history of lichen-forming fungi is primarily based on molecular dating approaches. These studies suggest extant clades of macrolichens diversified after the K-Pg boundary. Here we corroborate the mid-Mesozoic fossil Daohugouthallus ciliiferus as an epiphytic macrolichen that predates the K-Pg boundary by 100 Mys. Based on new material and geometric morphometric analysis, we demonstrate that the Jurassic fossil is morphologically most similar to Parmeliaceae, but cannot be placed in Parmeliaceae or other similar family-level clades forming macrolichens as these evolved much later. Consequently, a new family, Daohugouthallaceae, is proposed here to accommodate this fossil, which reveals macrolichens may have been diverse long before the Cenozoic diversification of extant lineages.

Pax1 and Pax9 synergistically regulate vertebral column development

Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5399-5408 ◽  
Author(s):  
H. Peters ◽  
B. Wilm ◽  
N. Sakai ◽  
K. Imai ◽  
R. Maas ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Vertebral Column ◽  
Cell Lineage ◽  
Axial Skeleton ◽  
Intervertebral Discs ◽  
Potential Interaction ◽  
Specific Cell ◽  
Gradual Loss ◽  
Vertebral Bodies

The paralogous genes Pax1 and Pax9 constitute one group within the vertebrate Pax gene family. They encode closely related transcription factors and are expressed in similar patterns during mouse embryogenesis, suggesting that Pax1 and Pax9 act in similar developmental pathways. We have recently shown that mice homozygous for a defined Pax1 null allele exhibit morphological abnormalities of the axial skeleton, which is not affected in homozygous Pax9 mutants. To investigate a potential interaction of the two genes, we analysed Pax1/Pax9 double mutant mice. These mutants completely lack the medial derivatives of the sclerotomes, the vertebral bodies, intervertebral discs and the proximal parts of the ribs. This phenotype is much more severe than that of Pax1 single homozygous mutants. In contrast, the neural arches, which are derived from the lateral regions of the sclerotomes, are formed. The analysis of Pax9 expression in compound mutants indicates that both spatial expansion and upregulation of Pax9 expression account for its compensatory function during sclerotome development in the absence of Pax1. In Pax1/Pax9 double homozygous mutants, formation and anteroposterior polarity of sclerotomes, as well as induction of a chondrocyte-specific cell lineage, appear normal. However, instead of a segmental arrangement of vertebrae and intervertebral disc anlagen, a loose mesenchyme surrounding the notochord is formed. The gradual loss of Sox9 and Collagen II expression in this mesenchyme indicates that the sclerotomes are prevented from undergoing chondrogenesis. The first detectable defect is a low rate of cell proliferation in the ventromedial regions of the sclerotomes after sclerotome formation but before mesenchymal condensation normally occurs. At later stages, an increased number of cells undergoing apoptosis further reduces the area normally forming vertebrae and intervertebral discs. Our results reveal functional redundancy between Pax1 and Pax9 during vertebral column development and identify an early role of Pax1 and Pax9 in the control of cell proliferation during early sclerotome development. In addition, our data indicate that the development of medial and lateral elements of vertebrae is regulated by distinct genetic pathways.

scholarly journals Single-cell lineages reveal the rates, routes, and drivers of metastasis in cancer xenografts

2020 ◽  
Author(s):  
Jeffrey J. Quinn ◽  
Matthew G. Jones ◽  
Ross A. Okimoto ◽  
Shigeki Nanjo ◽  
Michelle M. Chan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lung Cancer ◽  
Single Cell ◽  
Cancer Progression ◽  
Cell Lineage ◽  
Lineage Tracing ◽  
Rna Seq ◽  
Disease Etiology ◽  
Cell Lineages ◽  
Transient Events

AbstractCancer progression is characterized by rare, transient events which are nonetheless highly consequential to disease etiology and mortality. Detailed cell phylogenies can recount the history and chronology of these critical events – including metastatic seeding. Here, we applied our Cas9-based lineage tracer to study the subclonal dynamics of metastasis in a lung cancer xenograft mouse model, revealing the underlying rates, routes, and drivers of metastasis. We report deeply resolved phylogenies for tens of thousands of metastatically disseminated cancer cells. We observe surprisingly diverse metastatic phenotypes, ranging from metastasis-incompetent to aggressive populations. These phenotypic distinctions result from pre-existing, heritable, and characteristic differences in gene expression, and we demonstrate that these differentially expressed genes can drive invasiveness. Furthermore, metastases transit via diverse, multidirectional tissue routes and seeding topologies. Our work demonstrates the power of tracing cancer progression at unprecedented resolution and scale.One Sentence SummarySingle-cell lineage tracing and RNA-seq capture diverse metastatic behaviors and drivers in lung cancer xenografts in mice.

scholarly journals The pseudobranch of jawed vertebrates is a mandibular arch-derived gill

2021 ◽  
Author(s):  
Christine Hirschberger ◽  
J. Andrew Gillis
Keyword(s):  
Gene Expression ◽  
Cell Lineage ◽  
Cell Types ◽  
Cartilaginous Fish ◽  
Lineage Tracing ◽  
Gill Arch ◽  
Pharyngeal Arch ◽  
Anatomical Features ◽  
Mandibular Arch ◽  
Ancestral Origin

AbstractThe pseudobranch is a gill-like epithelial elaboration that sits behind the jaw of most fishes. This structure was classically regarded as a vestige of the ancestral gill-arch like condition of the gnathostome jaw. However, more recently, hypotheses of jaw evolution by transformation of a gill arch have been challenged, and the pseudobranch has alternatively been considered a specialised derivative of the second (hyoid) pharyngeal arch. Here, we demonstrate by cell lineage tracing in a cartilaginous fish, the skate (Leucoraja erinacea), that the pseudobranch does, in fact, derive from the mandibular arch, and that it shares gene expression features and cell types with gills. We also show that the mandibular arch pseudobranch is supported by a spiracular cartilage that is patterned by a shh-expressing epithelial signalling centre. This closely parallels the condition seen in the gill arches, where cartilaginous appendages called branchial rays supporting the respiratory lamellae of the gills are patterned by a shh-expressing gill arch epithelial ridge (GAER). Taken together, these findings support serial homology of the pseudobranch and gills, and an ancestral origin of gill arch-like anatomical features from the gnathostome mandibular arch.

scholarly journals Direct readout of neural stem cell transgenesis with an integration-coupled gene expression switch

2019 ◽  
Author(s):  
Takuma Kumamoto ◽  
Franck Maurinot ◽  
Raphaëlle Barry ◽  
Célia Vaslin ◽  
Sandrine Vandormael-Pournin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cell ◽  
Neural Stem Cell ◽  
Cell Lineage ◽  
Regulatory Elements ◽  
Lineage Tracing ◽  
Model Organisms ◽  
Genetic Switch

SUMMARYStable genomic integration of exogenous transgenes is critical for neurodevelopmental and neural stem cell studies. Despite the emergence of tools driving genomic insertion at high rates with DNA vectors, transgenesis procedures remain fundamentally hindered by the impossibility to distinguish integrated transgenes from residual episomes. Here, we introduce a novel genetic switch termed iOn that triggers gene expression upon insertion in the host genome, enabling simple, rapid and faithful identification of integration events following transfection with naked plasmids accepting large cargoes. In vitro, iOn permits rapid drug-free stable transgenesis of mouse and human pluripotent stem cells with multiple vectors. In vivo, we demonstrate accurate cell lineage tracing, assessment of regulatory elements and mosaic analysis of gene function in somatic transgenesis experiments that reveal new aspects of neural progenitor potentialities and interactions. These results establish iOn as an efficient and widely applicable strategy to report transgenesis and accelerate genetic engineering in cultured systems and model organisms.

Analysis of the differences between Syntormon pallipes and S. pseudospicatus (Diptera: Dolichopodidae): morphological and molecular data

2019 ◽  
Vol 28 (2) ◽  
pp. 305-316
Author(s):  
M.A. Chursina ◽  
I.Ya. Grichanov
Keyword(s):  
Dna Analysis ◽  
Distinct Species ◽  
Molecular Data ◽  
Wing Shape ◽  
Morphological Data ◽  
12S Rrna ◽  
Separate Species ◽  
Geometric Morphometric ◽  
Geometric Morphometric Analysis ◽  
Morphological And Molecular Data

The recent catalogues of the family Dolichopodidae considered Syntormon pallipes (Fabricius, 1794) and S. pseudospicatus Strobl, 1899 as separate species. In this study, we used three approaches to estimate the significance of differences between the two species: molecular analysis (COI and 12S rRNA sequences), analysis of leg colour characters and geometric morphometric analysis of wing shape. The morphological data confirmed the absence of significant differences between S. pallipes and S. pseudospicatus found in the DNA analysis. Significant differences in the wing shape of two species have not been revealed. Hence, according to our data, there is no reason to consider S. pseudospicatus as a distinct species.

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