Patterning the ascidian nervous system: structure, expression and transgenic analysis of the CiHox3 gene

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4737-4748 ◽  
Author(s):  
A. Locascio ◽  
F. Aniello ◽  
A. Amoroso ◽  
M. Manzanares ◽  
R. Krumlauf ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Hox Genes ◽  
Regional Identity ◽  
Regulatory Elements ◽  
System Structure ◽  
Anteroposterior Patterning ◽  
Hox Gene ◽  
The Central Nervous System ◽  
Group 3

Hox genes play a fundamental role in the establishment of chordate body plan, especially in the anteroposterior patterning of the nervous system. Particularly interesting are the anterior groups of Hox genes (Hox1-Hox4) since their expression is coupled to the control of regional identity in the anterior regions of the nervous system, where the highest structural diversity is observed. Ascidians, among chordates, are considered a good model to investigate evolution of Hox gene, organisation, regulation and function. We report here the cloning and the expression pattern of CiHox3, a Ciona intestinalis anterior Hox gene homologous to the paralogy group 3 genes. In situ hybridization at the larva stage revealed that CiHox3 expression was restricted to the visceral ganglion of the central nervous system. The presence of a sharp posterior boundary and the absence of transcript in mesodermal tissues are distinctive features of CiHox3 expression when compared to the paralogy group 3 in other chordates. We have investigated the regulatory elements underlying CiHox3 neural-specific expression and, using transgenic analysis, we were able to isolate an 80 bp enhancer responsible of CiHox3 activation in the central nervous system (CNS). A comparative study between mouse and Ciona Hox3 promoters demonstrated that divergent mechanisms are involved in the regulation of these genes in vertebrates and ascidians.

scholarly journals Analyses of temporal regulatory elements of the prosaposin gene in transgenic mice

2003 ◽  
Vol 370 (2) ◽  
pp. 557-566 ◽  
Author(s):  
Ying SUN ◽  
David P. WITTE ◽  
Peng JIN ◽  
Gregory A. GRABOWSKI
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Nervous System ◽  
Transgenic Mice ◽  
Peak Level ◽  
Regulatory Elements ◽  
Low Level ◽  
The Central Nervous System ◽  
Flanking Region ◽  
The Brain

The expression of prosaposin is temporally and spatially regulated at transcriptional and post-translational levels. Transgenic mice with various 5′-flanking deletions of the prosaposin promoter fused to luciferase (LUC) reporters were used to define its temporal regulatory region. LUC expression in the transgenic mice carrying constructs with 234bp (234LUC), 310bp (310LUC) or 2400bp (2400LUC) of the 5′-flanking region was analysed in the central nervous system and eye throughout development. For 310LUC and 2400LUC, low-level LUC activity was maintained until embryonal day 18 in brain, eye and spinal cord. The peak level of LUC activity was at birth, with return to a plateau (1/3 of peak) throughout adulthood. Deletion of the region that included the retinoic acid-receptor-related orphan receptor (RORα)-binding site and sequence-specific transcription factor (Sp1) cluster sites (44—310bp) suppressed the peak of activity. By comparison, the peak level for 234LUC was shifted 2 weeks into neonatal life in the brain, but not in the eye, and no peak of activity was observed in the spinal cord. The endogenous prosaposin mRNA in eye, spinal cord and cerebellum had low-level expression before birth and continued to increase into adulthood. In cerebrum, the endogenous mRNA showed similar expression profile to constructs 310LUC, 2400LUC and 234LUC, with the peak expression at 1 week and a decreased level in adult. In the brain of the newborn, 2400LUC was highly expressed in the trigeminal ganglion and brain stem regions when compared with the generalized expression pattern for endogenous prosaposin mRNA. These results suggest that the modifiers (RORα- and Sp1-binding sites) residing within 310bp of the 5′-flanking region mediate developmental regulation in the central nervous system and eye. Additional regulatory elements outside the 5′ region of the 2400bp promoter fragment appear to be essential for the physiological control of the prosaposin locus.

Receptors for Insulin-Like Growth Factors in the Central Nervous System: Structure and Function

1988 ◽  
Vol 20 (S 7) ◽  
pp. 436-442 ◽  
Author(s):  
S. Gammeltoft ◽  
R. Ballotti ◽  
F. Nielsen ◽  
Aline Kowalski ◽  
E. Van Obberghen
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Growth Factors ◽  
Structure And Function ◽  
System Structure ◽  
The Central Nervous System ◽  
And Function ◽  
Insulin Like Growth Factors

bFGF as a possible morphogen for the anteroposterior axis of the central nervous system in Xenopus

Development ◽  
1995 ◽  
Vol 121 (9) ◽  
pp. 3121-3130 ◽  
Author(s):  
M. Kengaku ◽  
H. Okamoto
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neural Development ◽  
Anteroposterior Patterning ◽  
Anteroposterior Axis ◽  
Spemann's Organizer ◽  
The Central Nervous System ◽  
Dorsal Ectoderm ◽  
Higher Doses

Vertebrate neural development is initiated during gastrulation by the inductive action of the dorsal mesoderm (Spemann's organizer in amphibians) on neighbouring ectoderm, which eventually gives rise to the central nervous system from forebrain to spinal cord. Here we present evidence that bFGF can mimic the organizer action by inducing Xenopus ectoderm cells in culture to express four position-specific neural markers (XeNK-2, En-2, XIHbox1 and XIHbox6) along the anteroposterior axis. bFGF also induced the expression of a general neural marker NCAM but not the expression of immediate-early mesoderm markers (goosecoid, noggin, Xbra and Xwnt-8), suggesting that bFGF directly neuralized ectoderm cells without forming mesodermal cells. The bFGF dose required to induce the position-specific markers was correlated with the anteroposterior location of their expression in vivo, with lower doses eliciting more anterior markers and higher doses more posterior markers. These data indicate that bFGF or its homologue is a promising candidate for a neural morphogen for anteroposterior patterning in Xenopus. Further, we showed that the ability of ectoderm cells to express the anterior markers in response to bFGF was lost by mid-gastrula, before the organizer mesoderm completely underlies the anterior dorsal ectoderm. Thus, an endogenous FGF-like molecule released from the involuting organizer may initiate the formation of the anteroposterior axis of the central nervous system during the early stages of gastrulation by forming a concentration gradient within the plane of dorsal ectoderm.

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