Role of Pax3/7 in the tectum regionalization

Development ◽  
2001 ◽  
Vol 128 (20) ◽  
pp. 4069-4077
Author(s):  
Eiji Matsunaga ◽  
Isato Araki ◽  
Harukazu Nakamura
Keyword(s):  
Optic Tectum ◽  
Normal Development ◽  
Marker Gene ◽  
Torus Semicircularis ◽  
Ventral Mesencephalon ◽  
Expression Domain ◽  
Dorsoventral Axis ◽  
Normal Expression ◽  
Sequential Induction

Pax3/7 is expressed in the alar plate of the mesencephalon. The optic tectum differentiates from the alar plate of the mesencephalon, and expression of Pax3/7 is well correlated to the tectum development. To explore the function of Pax3 and Pax7 in the tectum development, we misexpressed Pax3 and Pax7 in the diencephalon and ventral mesencephalon. Morphological and molecular marker gene analysis indicated that Pax3 and Pax7 misexpression caused fate change of the alar plate of the presumptive diencephalon to that of the mesencephalon, that is, a tectum and a torus semicircularis were formed ectopically. Ectopic tectum in the diencephalon appeared to be generated through sequential induction of Fgf8, En2 and Pax3/7. In ventral mesencephalon, which expresses En but does not differentiate to the tectum in normal development, Pax3 and Pax7 misexpression induced ectopic tectum. In normal development, Pax3 and Pax7 expression in the mesencephalon commences after Otx2, En and Pax2/5 expression. In addition, expression domain of Pax3 and Pax7 is well consistent with presumptive tectum region in a dorsoventral axis. Taken together with normal expression pattern of Pax3 and Pax7, results of misexpression experiments suggest that Pax3 and Pax7 define the tectum region subsequent to the function of Otx2 and En.

The homeodomain-containing gene Xdbx inhibits neuronal differentiation in the developing embryo

Development ◽  
2000 ◽  
Vol 127 (13) ◽  
pp. 2945-2954 ◽  
Author(s):  
A.A. Gershon ◽  
J. Rudnick ◽  
L. Kalam ◽  
K. Zimmerman
Keyword(s):  
Neuronal Differentiation ◽  
Normal Development ◽  
Early Embryo ◽  
Neural Plate ◽  
Neural Progenitors ◽  
Expression Domain ◽  
Basic Helix Loop Helix ◽  
Helix Loop Helix ◽  
Early Neurogenesis

The development of the vertebrate nervous system depends upon striking a balance between differentiating neurons and neural progenitors in the early embryo. Our findings suggest that the homeodomain-containing gene Xdbx regulates this balance by maintaining neural progenitor populations within specific regions of the neuroectoderm. In posterior regions of the Xenopus embryo, Xdbx is expressed in a bilaterally symmetric stripe that lies at the middle of the mediolateral axis of the neural plate. This stripe of Xdbx expression overlaps the expression domain of the proneural basic/helix-loop-helix-containing gene, Xash3, and is juxtaposed to the expression domains of Xenopus Neurogenin related 1 and N-tubulin, markers of early neurogenesis in the embryo. Xdbx overexpression inhibits neuronal differentiation in the embryo and when co-injected with Xash3, Xdbx inhibits the ability of Xash3 to induce ectopic neurogenesis. One role of Xdbx during normal development may therefore be to restrict spatially neuronal differentiation within the neural plate, possibly by altering the neuronal differentiation function of Xash3.

Evidence for a functional role of the cytoskeleton in determination of the dorsoventral axis in Xenopus laevis eggs

Development ◽  
1983 ◽  
Vol 77 (1) ◽  
pp. 15-37
Author(s):  
Geertje A. Ubbels ◽  
K. Hara ◽  
C. H. Koster ◽  
M. W. Kirschner
Keyword(s):  
Functional Role ◽  
Normal Development ◽  
Cytological Study ◽  
Time Lapse ◽  
Microtubule Assembly ◽  
Dorsoventral Axis ◽  
Normal Table ◽  
Fertilized Egg

A normal table of events of the first cleavage period in the fertilized egg (cf. Gerhart, 1980) has been completed (cf. Table I) by studying external and internal features. Through a cytological study of eggs fixed after video time-lapse observation such featurescan directly be correlated and it has been shown that the first postfertilization wave (PFW) reflects spermaster growth, which causes rearrangements of animal yolk material. Thismay, in conjunction with the interaction of the spermaster rays with the cortex, define, in time as well as in space, the asymmetric cortical contraction which we suppose to evoke asymmetry in the animal hemisphere by formation of the vitelline wall (Pasteels, 1964) and in the vegetal hemisphere by formation of the Vegetal Dorsalising Centre (Kirschneret al. 1981). Neither prick-activated eggs nor fertilized eggs incubated in vinblastine develop a spermaster. Under these conditions abnormal cytoplasmic segregation may be directed by gravity alone. For normal development the activated egg must in some way, for instance through the sperm centriole, organize microtubule assembly into a monaster. The centriole actsas a microtubule-organizing centre in structuring the egg's cytoskeleton, and through this directs localization of the various yolk components, in time as well as in space. In egg rotation experiments performed under appropriate conditions, the cytoskeleton is disturbed and yolk rearranges under gravity till a new equilibrium is established which determines a new dorsoventral polarity. Such experiments also show that neither the dorsal cytoplasm nor the grey crescent cortex act as the ultimate dorsal determinants, since their localization is unaltered upon rotation, whereas the overall yolk distribution is significantly changed.

Localization of Intracisternal a Particle Antigens in Neoplastic Cells and Preimplantation Mouse Embryos

1980 ◽  
Vol 38 ◽  
pp. 696-697
Author(s):  
Thomas T.F. Huang ◽  
Patricia G. Calarco
Keyword(s):  
Endoplasmic Reticulum ◽  
Normal Development ◽  
Mouse Embryos ◽  
Neoplastic Cells ◽  
Large Numbers ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Intracisternal A Particle ◽  
Normal Feature

The stage specific appearance of a retravirus, termed the Intracisternal A particle (IAP) is a normal feature of early preimplantation development. To date, all feral and laboratory strains of Mus musculus and even Asian species such as Mus cervicolor and Mus pahari express the particles during the 2-8 cell stages. IAP form by budding into the endoplasmic reticulum and appear singly or as groups of donut-shaped particles within the cisternae (fig. 1). IAP are also produced in large numbers in several neoplastic cells such as certain plasmacytomas and rhabdomyosarcomas. The role of IAP, either in normal development or in neoplastic behavior, is unknown.

scholarly journals Non-apoptotic enteroblast-specific role of the initiator caspase Dronc for development and homeostasis of the Drosophila intestine

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jillian L. Lindblad ◽  
Meghana Tare ◽  
Alla Amcheslavsky ◽  
Alicia Shields ◽  
Andreas Bergmann
Keyword(s):  
Normal Development ◽  
Cell Lineage ◽  
Cell Types ◽  
Specific Role ◽  
Mutant Phenotype ◽  
Apoptotic Pathway ◽  
Specific Expression ◽  
Card Domain

AbstractThe initiator caspase Dronc is the only CARD-domain containing caspase in Drosophila and is essential for apoptosis. Here, we report that homozygous dronc mutant adult animals are short-lived due to the presence of a poorly developed, defective and leaky intestine. Interestingly, this mutant phenotype can be significantly rescued by enteroblast-specific expression of dronc+ in dronc mutant animals, suggesting that proper Dronc function specifically in enteroblasts, one of four cell types in the intestine, is critical for normal development of the intestine. Furthermore, enteroblast-specific knockdown of dronc in adult intestines triggers hyperplasia and differentiation defects. These enteroblast-specific functions of Dronc do not require the apoptotic pathway and thus occur in a non-apoptotic manner. In summary, we demonstrate that an apoptotic initiator caspase has a very critical non-apoptotic function for normal development and for the control of the cell lineage in the adult midgut and therefore for proper physiology and homeostasis.

The Role of Galanin in Cerebellar Granule Cell Migration in the Early Postnatal Mouse during Normal Development and After Injury

2021 ◽  
pp. JN-RM-0900-15
Author(s):  
Yutaro Komuro ◽  
Ludovic Galas ◽  
Yury M. Morozov ◽  
Jennifer K. Fahrion ◽  
Emilie Raoult ◽  
...  
Keyword(s):  
Cell Migration ◽  
Granule Cell ◽  
Normal Development ◽  
Cerebellar Granule Cell ◽  
Cerebellar Granule

scholarly journals Successive specification of Drosophila neuroblasts NB 6-4 and NB 7-3 depends on interaction of the segment polarity genes wingless, gooseberry and naked cuticle

Development ◽  
2001 ◽  
Vol 128 (17) ◽  
pp. 3253-3261 ◽  
Author(s):  
Nirupama Deshpande ◽  
Rainer Dittrich ◽  
Gerhard M. Technau ◽  
Joachim Urban
Keyword(s):  
Cell Fate ◽  
Cell Lineage ◽  
Positional Information ◽  
Dorsoventral Patterning ◽  
Expression Domain ◽  
Direct Role ◽  
Segment Polarity Genes ◽  
Segment Polarity ◽  
Unique Identity

The Drosophila central nervous system derives from neural precursor cells, the neuroblasts (NBs), which are born from the neuroectoderm by the process of delamination. Each NB has a unique identity, which is revealed by the production of a characteristic cell lineage and a specific set of molecular markers it expresses. These NBs delaminate at different but reproducible time points during neurogenesis (S1-S5) and it has been shown for early delaminating NBs (S1/S2) that their identities depend on positional information conferred by segment polarity genes and dorsoventral patterning genes. We have studied mechanisms leading to the fate specification of a set of late delaminating neuroblasts, NB 6-4 and NB 7-3, both of which arise from the engrailed (en) expression domain, with NB 6-4 delaminating first. In contrast to former reports, we did not find any evidence for a direct role of hedgehog in the process of NB 7-3 specification. Instead, we present evidence to show that the interplay of the segmentation genes naked cuticle (nkd) and gooseberry (gsb), both of which are targets of wingless (wg) activity, leads to differential commitment to NB 6-4 and NB 7-3 cell fate. In the absence of either nkd or gsb, one NB fate is replaced by the other. However, the temporal sequence of delamination is maintained, suggesting that formation and specification of these two NBs are under independent control.

Microglial refinement of spinal cord sensory circuitry regulates normal maturation of dynamic touch.

2021 ◽  
Author(s):  
Yajing Xu ◽  
Stephanie Koch ◽  
Alexander Chamessian ◽  
Qianru He ◽  
Mayya Sundukova ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Normal Development ◽  
Physiological Role ◽  
Spinal Cord Dorsal Horn ◽  
Dynamic Touch ◽  
Tactile Sensitivity ◽  
Primary Afferent ◽  
Spinal Cord Dorsal

In the spinal cord dorsal horn, sensory circuits undergo remarkable postnatal reorganisation, including refinement of primary afferent A-fibres in the superficial layers, accompanied by decreased cutaneous sensitivity. Here we show a physiological role of microglia necessary for normal development of dorsal horn sensory circuits and tactile sensitivity. In the absence of microglial engulfment, superfluous A-fibre projections persist, leading to lifelong hypersensitivity to dynamic touch.

Suppression of GATA factor activity causes axis duplication in Xenopus

Development ◽  
1998 ◽  
Vol 125 (23) ◽  
pp. 4595-4605 ◽  
Author(s):  
T.G. Sykes ◽  
A.R. Rodaway ◽  
M.E. Walmsley ◽  
R.K. Patient
Keyword(s):  
Cell Fate ◽  
Homeobox Gene ◽  
Dominant Negative ◽  
Gata Factor ◽  
Dorsoventral Axis ◽  
Morphogenetic Protein ◽  
Head Formation ◽  
Bmp Signalling ◽  
Bmp Antagonist

In Xenopus, the dorsoventral axis is patterned by the interplay between active signalling in ventral territories, and secreted antagonists from Spemann's organiser. Two signals are important in ventral cells, bone morphogenetic protein-4 (BMP-4) and Wnt-8. BMP-4 plays a conserved role in patterning the vertebrate dorsoventral axis, whilst the precise role of Wnt-8 and its relationship with BMP-4, are still unclear. Here we have investigated the role played by the GATA family of transcription factors, which are expressed in ventral mesendoderm during gastrulation and are required for the differentiation of blood and endodermal tissues. Injection ventrally of a dominant-interfering GATA factor (called G2en) induced the formation of secondary axes that phenocopy those induced by the dominant-negative BMP receptor. However, unlike inhibiting BMP signalling, inhibiting GATA activity in the ectoderm does not lead to neuralisation. In addition, analysis of gene expression in G2en injected embryos reveals that at least one known target gene for BMP-4, the homeobox gene Vent-2, is unaffected. In contrast, the expression of Wnt-8 and the homeobox gene Vent-1 is suppressed by G2en, whilst the organiser-secreted BMP antagonist chordin becomes ectopically expressed. These data therefore suggest that GATA activity is essential for ventral cell fate and that subsets of ventralising and dorsalising genes require GATA activity for their expression and suppression, respectively. Finally, using G2en, we show that suppression of Wnt-8 expression, in conjunction with blocked BMP signalling, does not lead to head formation, suggesting that the head-suppressing Wnt signal may not be Wnt-8.

BMP signaling patterns the dorsal and intermediate neural tube via regulation of homeobox and helix-loop-helix transcription factors

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2459-2472 ◽  
Author(s):  
John R. Timmer ◽  
Charlotte Wang ◽  
Lee Niswander
Keyword(s):  
Transcription Factors ◽  
Neural Tube ◽  
Transforming Growth Factor ◽  
Cell Types ◽  
Neural Cell ◽  
Bmp Signaling ◽  
Expression Domain ◽  
Cell Identity ◽  
Dorsoventral Axis ◽  
Helix Loop Helix

In the spinal neural tube, populations of neuronal precursors that express a unique combination of transcription factors give rise to specific classes of neurons at precise locations along the dorsoventral axis. Understanding the patterning mechanisms that generate restricted gene expression along the dorsoventral axis is therefore crucial to understanding the creation of diverse neural cell types. Bone morphogenetic proteins (BMPs) and other transforming growth factor β (TGFβ) proteins are expressed by the dorsal-most cells of the neural tube (the roofplate) and surrounding tissues, and evidence indicates that they play a role in assigning cell identity. We have manipulated the level of BMP signaling in the chicken neural tube to show that BMPs provide patterning information to both dorsal and intermediate cells. BMP regulation of the expression boundaries of the homeobox proteins Pax6, Dbx2 and Msx1 generates precursor populations with distinct developmental potentials. Within the resulting populations, thresholds of BMP act to set expression domain boundaries of developmental regulators of the homeobox and basic helix-loop-helix (bHLH) families, ultimately leading to the generation of a diversity of differentiated neural cell types. This evidence strongly suggests that BMPs are the key regulators of dorsal cell identity in the spinal neural tube.

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