Direct and indirect roles of CNS dorsal midline cells in choroid plexus epithelia formation

A series of gain- or loss-of-function experiments performed in different vertebrate species have demonstrated that the Engrailed genes play multiple roles during brain development. In particular, they have been implicated in the determination of the mid/hindbrain domain, in cell proliferation and survival, in neurite formation, tissue polarization and axonal pathfinding. We have analyzed the consequences of a local gain of En function within or adjacent to the endogenous expression domain in mouse and chick embryos. In WEXPZ.En1 transgenic mice (Danielian, P. S. and McMahon, A. P. (1996) Nature 383, 332–334) several genes are induced as a consequence of ectopic expression of En1 in the diencephalic roof (but in a pattern inconsistent with a local di- to mes-encephalon fate change). The development of several structures with secretory function, generated from the dorsal neuroepithelium, is severely compromised. The choroid plexus, subcommissural organ and pineal gland either fail to form or are atrophic. These defects are preceded by an increase in cell death at the dorsal midline. Comparison with the phenotype of Wnt1(sw/sw) (swaying) mutants suggests that subcommissural organ failure is the main cause of prenatal hydrocephalus observed in both strains. The formation of the posterior commissure is also delayed, and errors in axonal pathfinding are frequent. In chick, ectopic expression of En by in ovo electroporation, affects growth and differentiation of the choroid plexus.

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Genes involved in forebrain development in the zebrafish, Danio rerio

Development ◽

10.1242/dev.123.1.191 ◽

1996 ◽

Vol 123 (1) ◽

pp. 191-203 ◽

Cited By ~ 19

Author(s):

C.P. Heisenberg ◽

M. Brand ◽

Y.J. Jiang ◽

R.M. Warga ◽

D. Beuchle ◽

...

Keyword(s):

Danio Rerio ◽

Embryonic Axis ◽

Dorsal Midline ◽

Forebrain Development ◽

Roof Plate ◽

Partial Fusion ◽

Anterior Forebrain ◽

Plate Analysis ◽

Midline Cells ◽

Mutant Phenotypes

We identified four zebrafish mutants with defects in forebrain induction and patterning during embryogenesis. The four mutants define three genes: masterblind (mbl), silberblick (slb), and knollnase (kas). In mbl embryos, the anterior forebrain acquires posterior forebrain characteristics: anterior structures such as the eyes, olfactory placodes and the telencephalon are missing, whereas the epiphysis located in the posterior forebrain is expanded. In slb embryos, the extension of the embryonic axis is initially delayed and eventually followed by a partial fusion of the eyes. Finally, in kas embryos, separation of the telencephalic primordia is incomplete and dorsal midline cells fail to form a differentiated roof plate. Analysis of the mutant phenotypes indicates that we have identified genes essential for the specification of the anterior forebrain (mbl), positioning of the eyes (slb) and differentiation of the roof plate (kas). In an appendix to this study we list mutants showing alterations in the size of the eyes and abnormal differentiation of the lenses.

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Linkage of cardiac left-right asymmetry and dorsal-anterior development in Xenopus

Development ◽

10.1242/dev.121.5.1467 ◽

1995 ◽

Vol 121 (5) ◽

pp. 1467-1474 ◽

Cited By ~ 21

Author(s):

M.C. Danos ◽

H.J. Yost

Keyword(s):

Cell Cycle ◽

Spatial Patterns ◽

Organizer Region ◽

Common Mechanism ◽

Contrast Injection ◽

Dorsal Midline ◽

Heart Looping ◽

Left Right Asymmetry ◽

Midline Cells ◽

Anterior Posterior

The left-right body axis is defined relative to the dorsal-ventral and anterior-posterior body axes. Since left-right asymmetries are not randomly oriented with respect to dorsal-ventral and anterior-posterior spatial patterns, it is possible that a common mechanism determines all three axes in a coordinate manner. Two approaches were undertaken to determine whether alteration in dorsal-anterior development perturbs the left-right orientation of heart looping. Treatments known to decrease dorsal-anterior development in Xenopus laevis, UV irradiation during the first cell cycle or Xwnt-8 DNA injections into dorsal blastomeres, caused an increase in cardiac left-right reversals. The frequency of left-right reversal was correlated with the severity of dorsal-anterior perturbation and with the extent of anterior notochord regression. Injection of Xwnt-8 DNA into dorsal midline cells resulted in decreased dorsal-anterior development and a correlated increase in cardiac left-right reversals. In contrast, injection of Xwnt-8 DNA into cardiac progenitor blastomeres did not result in left-right reversals, and dorsal-anterior development and notochord formation were normal. Disrupting development of dorsal-anterior cells, including cells that give rise to the Organizer region and the notochord, results in the randomization of cardiac left-right asymmetry. These results suggest dorsal-anterior development and the regulation of left-right orientation are linked.

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Hox-7 expression during murine craniofacial development

Development ◽

10.1242/dev.113.2.601 ◽

1991 ◽

Vol 113 (2) ◽

pp. 601-611 ◽

Cited By ~ 8

Author(s):

A. MacKenzie ◽

M.W. Ferguson ◽

P.T. Sharpe

Keyword(s):

Nervous System ◽

Choroid Plexus ◽

Expression Pattern ◽

Neural Tube ◽

Anterior Pituitary ◽

Expression Patterns ◽

In Situ Hybridisation ◽

Cell Types ◽

Subsequent Formation ◽

Dorsal Midline

We have used in situ hybridisation to establish the temporal and spatial expression patterns of the mouse homeobox-containing gene; Hox-7, in the developing embryonic cranium and nervous system of the mouse between embryonic days 9.5 (E9.5) and E15.5. Hox-7 has previously been associated with areas of mesenchymal-epithelial interaction and cell migration especially in neural crest ectomesenchymal cells. Aside from the expression patterns seen in the facial anlage at E9.5, Hox-7 transcripts were also detected in the neuroepithelium including cells of the dorsal midline of the neural tube. This expression pattern persisted throughout the embryonic time span studied. At E11.5, expression of Hox-7 became obvious in the neuroepithelium of the forming tela choroida and the telencephelii in areas destined to form the choroid plexus before any atrophy of the neuroepithelium took place. High expression of Hox-7 was also present in the mesenchyme cells invading the pouch formed by the involuting choroid plexus neuroepithelium. A second major site where Hox-7 was expressed was the anlage of the anterior pituitary; the Rathke's pouch. Expression became obvious at E10.5 throughout the pouch but by E12.5 became more regionalised in areas of the pouch destined to form the pars distalis. Hox-7 was also expressed in the forming meninges and skull bone precursors from E10.5 onwards. Expression of the Hox-7 gene is also seen in the external ear, the forming eye, the nasal pits and forming Jacobson's organs. When these expression patterns are considered together with characterised human and mouse retinoic acid embryopathies and the congenital malformations seen in human children associated with deletion of chromosome 4p16.1 (Wolf-Hirschhorn syndrome), Hox-7 may be a good candidate as one of the genes involved in the initiation of the choroid plexus phenotype and its subsequent formation, the formation of the outer ear, formation of the dentition and the differentiation of the cell types of the anterior pituitary. The expression pattern of Hox-7 in the dorsal midline of the neural tube further suggests that it may also be involved in the specification of the dorsal-ventral axis of the developing nervous system.

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Restricted expression of latexin in dorsal midline cells of developing rat forebrain

Neuroreport ◽

10.1097/00001756-199501000-00014 ◽

1995 ◽

Vol 6 (2) ◽

pp. 281-283 ◽

Cited By ~ 7

Author(s):

Keiko Takiguchi-Hayashi ◽

Yasuyoshi Arimatsu

Keyword(s):

Dorsal Midline ◽

Rat Forebrain ◽

Midline Cells ◽

Developing Rat

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Rmst Is a Novel Marker for the Mouse Ventral Mesencephalic Floor Plate and the Anterior Dorsal Midline Cells

PLoS ONE ◽

10.1371/journal.pone.0008641 ◽

2010 ◽

Vol 5 (1) ◽

pp. e8641 ◽

Cited By ~ 28

Author(s):

Christopher W. Uhde ◽

Joaquim Vives ◽

Ines Jaeger ◽

Meng Li

Keyword(s):

Floor Plate ◽

Dorsal Midline ◽

Anterior Dorsal ◽

Ventral Mesencephalic ◽

Midline Cells

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Organization of tight junctions in the choroid plexus epithelium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082546 ◽

1978 ◽

Vol 36 (2) ◽

pp. 336-337

Author(s):

B. Van Deurs ◽

J. K. Koehler

Keyword(s):

Choroid Plexus ◽

Present Report ◽

Freeze Fracture ◽

Barrier Properties ◽

Cell Junctions ◽

Structural Basis ◽

Apical Surface ◽

Choroid Plexus Epithelium ◽

Solid Nitrogen ◽

Special Composition

The choroid plexus epithelium constitutes a blood-cerebrospinal fluid (CSF) barrier, and is involved in regulation of the special composition of the CSF. The epithelium is provided with an ouabain-sensitive Na/K-pump located at the apical surface, actively pumping ions into the CSF. The choroid plexus epithelium has been described as “leaky” with a low transepithelial resistance, and a passive transepithelial flux following a paracellular route (intercellular spaces and cell junctions) also takes place. The present report describes the structural basis for these “barrier” properties of the choroid plexus epithelium as revealed by freeze fracture.Choroid plexus from the lateral, third and fourth ventricles of rats were used. The tissue was fixed in glutaraldehyde and stored in 30% glycerol. Freezing was performed either in liquid nitrogen-cooled Freon 22, or directly in a mixture of liquid and solid nitrogen prepared in a special vacuum chamber. The latter method was always used, and considered necessary, when preparations of complementary (double) replicas were made.

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Scanning electron microscopy of the integument of schistosoma rodhaini

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014230x ◽

1986 ◽

Vol 44 ◽

pp. 132-133

Author(s):

P. Evers ◽

C. Schutte ◽

C. D. Dettman

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Oral Sucker ◽

Adult Male ◽

Dorsal Surface ◽

Ventral Surface ◽

Sensory Receptors ◽

East African ◽

Dorsal Midline ◽

Scanning Electron

S.rodhaini (Brumpt 1931) is a parasite of East African rodents which may possibly hybridize with the human schistosome S. mansoni. The adult male at maturity measures approximately 3mm long and possesses both oral and ventral suckers and a marked gynaecophoric canal. The oral sucker is surrounded by a ring of sensory receptors with a large number of inwardly-pointing spines set into deep sockets occupying the bulk of the ventral surface of the sucker. Numbers of scattered sensory receptors are found on both dorsal and ventral surfaces of the head (Fig. 1) together with two conspicuous rows of receptors situated symmetrically on each side of the midline. One row extends along the dorsal surface of the head midway between the dorsal midline and the lateral margin.

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