Bimodal control of Hoxd gene transcription in the spinal cord defines two regulatory subclusters

P. Tschopp; A. J. Christen; D. Duboule

doi:10.1242/dev.076794

Hypothalamic A11 Nuclei Regulate the Circadian Rhythm of the Mechanonociception and the Spinal Clock Gene Transcription through Dopamine Receptor Activation

10.20944/preprints202009.0188.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Celia Piña-Leyva ◽

Manuel Lara-Lozano ◽

Marina Rodríguez-Sánchez ◽

Guadalupe C. Vidal-Cantú ◽

Erika Zavalza-Barrientos ◽

...

Keyword(s):

Spinal Cord ◽

Gene Transcription ◽

Clock Gene ◽

Clock Genes ◽

Receptor Activation ◽

Orphan Receptor ◽

Lumbar Spinal Cord ◽

Withdrawal Threshold ◽

Aryl Hydrocarbon ◽

Lumbar Spinal

Patients with degenerative diseases refer to feeling more pain during the night. However, it is unknown whether spinal nociception can be circadian and how is it controlled. We investigated whether the paw withdrawal threshold (PWT) could exhibit physiological circadian behavior as well as the contribution of the dopaminergic A11 nucleus and the spinal dopamine (DA) receptors (DRs) on the circadian PWT and the spinal clock gene transcription. Results revealed that control rats present a circadian PWT. Injecting 6-hydroxidopamine (6-OHDA) into the dopaminergic A11 nucleus reduced DA tissue content in the lumbar spinal cord, abolished the circadian PWT, induced allodynia, and reduced Period 1 and 2 (Per1 and 2), retinoid-related orphan receptor α (Rorα), Cryptochrome 1 (Cry1), and brain and muscle aryl-hydrocarbon receptor nuclear translocator-like protein (Bmal) mRNA. Likewise, administration of D1-like and D2-like DR antagonists blunted circadian PWT, producing allodynia, and altered the clock genes mRNA. In contrast, administration of D1-like or D2-like DR agonists blocked 6-OHDA-induced allodynia. This study shows that the spinal cord has physiological circadian PWT, which is modulated by the descending dopaminergic A11 through differential activation of the spinal DRs. Also, A11 nuclei and spinal DRs can regulate the clock gene transcription, which can likely modulate the circadian PWT.

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Motoneuron fate specification revealed by patterned LIM homeobox gene expression in embryonic zebrafish

Development ◽

10.1242/dev.121.12.4117 ◽

1995 ◽

Vol 121 (12) ◽

pp. 4117-4125 ◽

Cited By ~ 37

Author(s):

B. Appel ◽

V. Korzh ◽

E. Glasgow ◽

S. Thor ◽

T. Edlund ◽

...

Keyword(s):

Gene Expression ◽

Spinal Cord ◽

Gene Transcription ◽

Cell Body ◽

Homeobox Genes ◽

Homeobox Gene ◽

Positional Information ◽

Axonal Projection ◽

Fate Specification ◽

Genes Expression

In zebrafish, individual primary motoneurons can be uniquely identified by their characteristic cell body positions and axonal projection patterns. The fate of individual primary motoneurons remains plastic until just prior to axogenesis when they become committed to particular identities. We find that distinct primary motoneurons express particular combinations of LIM homeobox genes. Expression precedes axogenesis as well as commitment, suggesting that LIM homeobox genes may contribute to the specification of motoneuronal fates. By transplanting them to new spinal cord positions, we demonstrate that primary motoneurons can initiate a new program of LIM homeobox gene expression, as well as the morphological features appropriate for the new position. We conclude that the patterned distribution of different primary motoneuronal types within the zebrafish spinal cord follows the patterned expression of LIM homeobox genes, and that this reflects a highly resolved system of positional information controlling gene transcription.

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