scholarly journals Cohesin components Stag1 and Stag2 differentially influence haematopoietic mesoderm development in zebrafish embryos

2020 ◽  
Author(s):  
Sarada Ketharnathan ◽  
Anastasia Labudina ◽  
Julia A. Horsfield
Keyword(s):  
Expression Patterns ◽  
Regulation Of Gene Expression ◽  
Three Dimensional ◽  
Genetic Dissection ◽  
Lateral Plate Mesoderm ◽  
Loss Of Function ◽  
Lateral Plate ◽  
Mesoderm Development ◽  
The Individual ◽  
Primitive Erythropoiesis

AbstractCohesin is a multiprotein complex made up of core subunits Smc1, Smc3 and Rad21, and either Stag1 or Stag2. Normal haematopoietic development relies on crucial functions of cohesin in cell division and regulation of gene expression via three-dimensional chromatin organisation. Cohesin subunit STAG2 is frequently mutated in myeloid malignancies, but the individual contributions of Stag variants to haematopoiesis or malignancy are not fully understood. Zebrafish have four Stag paralogues (Stag1a, Stag1b, Stag2a and Stag2b), allowing detailed genetic dissection of the contribution of Stag1-cohesin and Stag2-cohesin to development. Here we characterize for the first time the expression patterns and functions of zebrafish stag genes during embryogenesis. Using loss-of-function CRISPR-Cas9 zebrafish mutants, we show that stag1a and stag2b contribute to primitive embryonic haematopoiesis. Both stag1a and stag2b mutants present with erythropenia by 24 hours post-fertilisation. Homozygous loss of either paralog alters the number of haematopoietic/vascular progenitors in the lateral plate mesoderm. The lateral plate mesoderm zone of scl-positive cells is expanded in stag1a mutants with concomitant loss of kidney progenitors, and the number of spi1-positive cells are increased, consistent with skewing toward primitive myelopoiesis. In contrast, stag2b mutants have reduced haematopoietic/vascular mesoderm and downregulation of primitive erythropoiesis. Our results suggest that Stag1 and Stag2 proteins cooperate to balance the production of primitive haematopoietic/vascular progenitors from mesoderm.

scholarly journals Cohesin Components Stag1 and Stag2 Differentially Influence Haematopoietic Mesoderm Development in Zebrafish Embryos

2020 ◽  
Vol 8 ◽  
Author(s):  
Sarada Ketharnathan ◽  
Anastasia Labudina ◽  
Julia A. Horsfield
Keyword(s):  
Expression Patterns ◽  
Regulation Of Gene Expression ◽  
Three Dimensional ◽  
Genetic Dissection ◽  
Lateral Plate Mesoderm ◽  
Loss Of Function ◽  
Lateral Plate ◽  
Mesoderm Development ◽  
The Individual ◽  
Primitive Erythropoiesis

Cohesin is a multiprotein complex made up of core subunits Smc1, Smc3, and Rad21, and either Stag1 or Stag2. Normal haematopoietic development relies on crucial functions of cohesin in cell division and regulation of gene expression via three-dimensional chromatin organization. Cohesin subunit STAG2 is frequently mutated in myeloid malignancies, but the individual contributions of Stag variants to haematopoiesis or malignancy are not fully understood. Zebrafish have four Stag paralogues (Stag1a, Stag1b, Stag2a, and Stag2b), allowing detailed genetic dissection of the contribution of Stag1-cohesin and Stag2-cohesin to development. Here we characterize for the first time the expression patterns and functions of zebrafish stag genes during embryogenesis. Using loss-of-function CRISPR-Cas9 zebrafish mutants, we show that stag1a and stag2b contribute to primitive embryonic haematopoiesis. Both stag1a and stag2b mutants present with erythropenia by 24 h post-fertilization. Homozygous loss of either paralogue alters the number of haematopoietic/vascular progenitors in the lateral plate mesoderm. The lateral plate mesoderm zone of scl-positive cells is expanded in stag1a mutants with concomitant loss of kidney progenitors, and the number of spi1-positive cells are increased, consistent with skewing toward primitive myelopoiesis. In contrast, stag2b mutants have reduced haematopoietic/vascular mesoderm and downregulation of primitive erythropoiesis. Our results suggest that Stag1 and Stag2 proteins cooperate to balance the production of primitive haematopoietic/vascular progenitors from mesoderm.

The nature and development of cancer: Cancer mutations and their implications

2020 ◽  
pp. 445-455
Author(s):  
James D. Brenton ◽  
Tim Eisen
Keyword(s):  
Protein Function ◽  
Chromosomal Rearrangements ◽  
Regulation Of Gene Expression ◽  
Tumour Suppressor Genes ◽  
Cancer Type ◽  
Loss Of Function ◽  
Physiological Control ◽  
Cellular Processes ◽  
Cancer Mutations ◽  
The Individual

Cancer is a genetic disease in which progressive accumulation of mutations in the genome of somatic cells induces abnormal biological capabilities. Cancer-inducing mutations may originate from single base substitutions or large chromosomal rearrangements; but ultimately they disrupt normal cellular processes by altering protein function or disturbing the regulation of gene expression. Loss-of-function mutations in tumour suppressor genes inactivate physiological control of cell processes, whereas gain-of-function mutations directly affect physiological networks and, for example, induce pathological activation of signalling pathways. For many common cancers, we are now close to defining unique sets of somatic alterations which confer a specific signature of the cancer type and are also highly specific to the individual patient.

Comparison Between Healthy and Reduced Hand Function Using Ranges of Motion and a Weighted Fingertip Space Model

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Samuel T. Leitkam ◽  
Tamara Reid Bush
Keyword(s):  
Dimensional Space ◽  
Hand Function ◽  
Three Dimensional ◽  
Loss Of Function ◽  
Healthy Individuals ◽  
Model Calculations ◽  
Hand Model ◽  
Functional Models ◽  
Distal Interphalangeal ◽  
The Individual

Detection and quantification of changes in hand function are important for patients with loss of function and clinicians who are treating them. A recently developed model, the weighted fingertip space (WFS) quantifies the hand function of individuals in three-dimensional space and applies kinematic weighting parameters to identify regions of reachable space with high and low hand function. The goal of this research was to use the WFS model to compare and contrast the functional abilities of healthy individuals with the abilities of individuals with reduced functionality due to arthritis (RFA). Twenty two individuals with no reported issues with hand function and 21 individuals with arthritis affecting the hand were included in the research. Functional models were calculated from the ranges of motion and hand dimension data for each individual. Each model showed the volume of reachable space for each fingertip of each hand, the number of ways to reach a point in space, the range of fingertip orientations possible at each point, and the range of possible force application directions (FADs) at each point. In addition, two group models were developed that showed how many individuals in both the healthy and RFA groups were able to reach the same points in space. The results showed differences between the two groups for the range of motion (ROM) measurements, the individual model calculations, and the group models. The ROM measurements showed significant differences for the joints of the thumb, extension of the nonthumb metacarpophalangeal (MCP) joints, and flexion of the distal interphalangeal (DIP) joints. Comparing the models, the two groups qualitatively showed similar patterns of functional measures in space, but with the RFA group able to reach a smaller volume of space. Quantitatively, the RFA group showed trends of smaller values for all of the calculated functional weighting parameters and significantly smaller reachable volume for all of the fingers. The group models showed that all healthy individuals were able to reach an overlapping space, while 18 of 21 RFA individuals were able to reach similar spaces. Combined, the results showed that the WFS model presents the abilities of the hand in ways that can be quantitatively and qualitatively compared. Thus, the potential of this hand model is that it could be used to assess and document the changes that occur in hand function due to rehabilitation or surgery, or as a guide to determine areas most accessible by various populations.

scholarly journals Human iPS-derived pre-epicardial cells direct cardiomyocyte aggregation expansion and organization in vitro

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jun Jie Tan ◽  
Jacques P. Guyette ◽  
Kenji Miki ◽  
Ling Xiao ◽  
Gurbani Kaur ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Spatial Organization ◽  
Three Dimensional ◽  
Calcium Handling ◽  
Lateral Plate Mesoderm ◽  
Lateral Plate ◽  
Epicardial Cells ◽  
Tissue Organization ◽  
Cell Layers

AbstractEpicardial formation is necessary for normal myocardial morphogenesis. Here, we show that differentiating hiPSC-derived lateral plate mesoderm with BMP4, RA and VEGF (BVR) can generate a premature form of epicardial cells (termed pre-epicardial cells, PECs) expressing WT1, TBX18, SEMA3D, and SCX within 7 days. BVR stimulation after Wnt inhibition of LPM demonstrates co-differentiation and spatial organization of PECs and cardiomyocytes (CMs) in a single 2D culture. Co-culture consolidates CMs into dense aggregates, which then form a connected beating syncytium with enhanced contractility and calcium handling; while PECs become more mature with significant upregulation of UPK1B, ITGA4, and ALDH1A2 expressions. Our study also demonstrates that PECs secrete IGF2 and stimulate CM proliferation in co-culture. Three-dimensional PEC-CM spheroid co-cultures form outer smooth muscle cell layers on cardiac micro-tissues with organized internal luminal structures. These characteristics suggest PECs could play a key role in enhancing tissue organization within engineered cardiac constructs in vitro.

scholarly journals Unexpected contribution of fibroblasts to muscle lineage as a mechanism for limb muscle patterning

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Joana Esteves de Lima ◽  
Cédrine Blavet ◽  
Marie-Ange Bonnin ◽  
Estelle Hirsinger ◽  
Glenda Comai ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Lineage Tracing ◽  
Myotendinous Junction ◽  
Genetic Lineage ◽  
Limb Muscle ◽  
Lateral Plate Mesoderm ◽  
Loss Of Function ◽  
Sequencing Data ◽  
Lateral Plate ◽  
Bmp Signalling

AbstractPositional information driving limb muscle patterning is contained in connective tissue fibroblasts but not in myogenic cells. Limb muscles originate from somites, while connective tissues originate from lateral plate mesoderm. With cell and genetic lineage tracing we challenge this model and identify an unexpected contribution of lateral plate-derived fibroblasts to the myogenic lineage, preferentially at the myotendinous junction. Analysis of single-cell RNA-sequencing data from whole limbs at successive developmental stages identifies a population displaying a dual muscle and connective tissue signature. BMP signalling is active in this dual population and at the tendon/muscle interface. In vivo and in vitro gain- and loss-of-function experiments show that BMP signalling regulates a fibroblast-to-myoblast conversion. These results suggest a scenario in which BMP signalling converts a subset of lateral plate mesoderm-derived cells to a myogenic fate in order to create a boundary of fibroblast-derived myonuclei at the myotendinous junction that controls limb muscle patterning.

scholarly journals Essential roles of zebrafish bmp2a, fgf10, and fgf24 in the specification of the ventral pancreas

2012 ◽  
Vol 23 (5) ◽  
pp. 945-954 ◽  
Author(s):  
François Naye ◽  
Marianne L. Voz ◽  
Nathalie Detry ◽  
Matthias Hammerschmidt ◽  
Bernard Peers ◽  
...  
Keyword(s):  
Fibroblast Growth ◽  
Lateral Plate Mesoderm ◽  
Loss Of Function ◽  
Lateral Plate ◽  
Bmp Pathway ◽  
Ventral Pancreas ◽  
Pancreas Agenesis ◽  
Gut Endoderm ◽  
Hepatic Markers

In vertebrates, pancreas and liver arise from bipotential progenitors located in the embryonic gut endoderm. Bone morphogenic protein (BMP) and fibroblast growth factor (FGF) signaling pathways have been shown to induce hepatic specification while repressing pancreatic fate. Here we show that BMP and FGF factors also play crucial function, at slightly later stages, in the specification of the ventral pancreas. By analyzing the pancreatic markers pdx1, ptf1a, and hlxb9la in different zebrafish models of BMP loss of function, we demonstrate that the BMP pathway is required between 20 and 24 h postfertilization to specify the ventral pancreatic bud. Knockdown experiments show that bmp2a, expressed in the lateral plate mesoderm at these stages, is essential for ventral pancreas specification. Bmp2a action is not restricted to the pancreatic domain and is also required for the proper expression of hepatic markers. By contrast, through the analysis of fgf10−/−; fgf24−/− embryos, we reveal the specific role of these two FGF ligands in the induction of the ventral pancreas and in the repression of the hepatic fate. These mutants display ventral pancreas agenesis and ectopic masses of hepatocytes. Overall, these data highlight the dynamic role of BMP and FGF in the patterning of the hepatopancreatic region.

scholarly journals Genetic dissection of nodal function in patterning the mouse embryo

Development ◽  
2001 ◽  
Vol 128 (10) ◽  
pp. 1831-1843 ◽  
Author(s):  
L.A. Lowe ◽  
S. Yamada ◽  
M.R. Kuehn
Keyword(s):  
Mouse Embryo ◽  
Transforming Growth Factor ◽  
Function Analysis ◽  
Conclusive Evidence ◽  
Genetic Dissection ◽  
Loss Of Function ◽  
Developmental Processes ◽  
Mesoderm Development ◽  
Critical Thresholds ◽  
Hypomorphic Allele

Loss-of-function analysis has shown that the transforming growth factor-like signaling molecule nodal is essential for mouse mesoderm development. However, definitive proof of nodal function in other developmental processes in the mouse embryo has been lacking because the null mutation blocks gastrulation. We describe the generation and analysis of a hypomorphic nodal allele. Mouse embryos heterozygous for the hypomorphic allele and a null allele undergo gastrulation but then display abnormalities that fall into three distinct mutant phenotypic classes, which may result from expression levels falling below critical thresholds in one or more domains of nodal expression. Our analysis of each of these classes provides conclusive evidence for nodal-mediated regulation of several developmental processes in the mouse embryo, beyond its role in mesoderm formation. We find that nodal signaling is required for correct positioning of the anteroposterior axis, normal anterior and midline patterning, and the left-right asymmetric development of the heart, vasculature, lungs and stomach.

scholarly journals BMP signalling directs a fibroblast-to-myoblast conversion at the connective tissue/muscle interface to pattern limb muscles

2020 ◽  
Author(s):  
Joana Esteves de Lima ◽  
Cédrine Blavet ◽  
Marie-Ange Bonnin ◽  
Estelle Hirsinger ◽  
Glenda Comai ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Limb Development ◽  
Lineage Tracing ◽  
Genetic Lineage ◽  
Lateral Plate Mesoderm ◽  
Loss Of Function ◽  
Sequencing Data ◽  
Lateral Plate ◽  
Myogenic Cells ◽  
Bmp Signalling

AbstractPositional information driving limb muscle patterning is contained in lateral plate mesoderm-derived tissues, such as tendon or muscle connective tissue but not in myogenic cells themselves. The long-standing consensus is that myogenic cells originate from the somitic mesoderm, while connective tissue fibroblasts originate from the lateral plate mesoderm. We challenged this model using cell and genetic lineage tracing experiments in birds and mice, respectively, and identified a subpopulation of myogenic cells at the muscle tips close to tendons originating from the lateral plate mesoderm and derived from connective tissue gene lineages. Analysis of single-cell RNA-sequencing data obtained from limb cells at successive developmental stages revealed a subpopulation of cells displaying a dual muscle and connective tissue signature, in addition to independent muscle and connective tissue populations. Active BMP signalling was detected in this junctional cell sub-population and at the tendon/muscle interface in developing limbs. BMP gain- and loss-of-function experiments performed in vivo and in vitro showed that this signalling pathway regulated a fibroblast-to-myoblast conversion. We propose that localised BMP signalling converts a subset of lateral plate mesoderm-derived fibroblasts to a myogenic fate and establishes a boundary of fibroblast-derived myonuclei at the muscle/tendon interface to control the muscle pattern during limb development.

scholarly journals Endocardial differentiation in zebrafish occurs during early somitogenesis and is dependent on BMP and etv2 signalling

2019 ◽  
Author(s):  
Samuel J Capon ◽  
Kelly A Smith
Keyword(s):  
Vascular Endothelial ◽  
Lateral Plate Mesoderm ◽  
Loss Of Function ◽  
Lateral Plate ◽  
Molecular Identity ◽  
Cardiovascular Biology ◽  
Bmp Signalling ◽  
Anterior Lateral Plate Mesoderm ◽  
Function Models ◽  
Signalling Cascade

AbstractThe endocardium and adjacent vascular endothelial network share a number of molecular markers however there are distinct physiological functions of these tissues. What distinguishes these lineages on a molecular level remains an important, unanswered question in cardiovascular biology. We have identified the Gt(SAGFF27C); Tg(4xUAS:egfp) line as a marker of early endocardial development and used this line to examine endocardial differentiation. Our results show that the endocardium emerges from the anterior lateral plate mesoderm at the 8-somite stage (13 hpf). Analysis in a number of loss-of-function models showed that whilst nkx2.5, hand2 and tal1 loss-of-function have no effect on the endocardial progenitor domain, both etv2 loss-of-function and inhibition of BMP signalling reduce the endocardial domain. Furthermore, manipulating BMP signalling alters etv2 expression. Together, these results describe the onset of endocardial molecular identity and suggest a signalling cascade whereby BMP signalling acts upstream of etv2 to direct differentiation of endocardial progenitors.

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