scholarly journals Sonic hedgehog specifies flight feather positional information in avian wings

Development ◽  
2020 ◽  
Vol 147 (9) ◽  
pp. dev188821
Author(s):  
Lara Busby ◽  
Cristina Aceituno ◽  
Caitlin McQueen ◽  
Constance A. Rich ◽  
Maria A. Ros ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Positional Information ◽  
Flight Feather

scholarly journals A positional information gradient of sonic hedgehog is required for flight feather formation in avian wings

2019 ◽  
Author(s):  
Lara Busby ◽  
Cristina Aceituno ◽  
Caitlin McQueen ◽  
Constance A. Rich ◽  
Maria A. Ros ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Limb Development ◽  
Positional Information ◽  
Embryonic Chick ◽  
Flight Feather ◽  
Avian Flight ◽  
Theropod Dinosaurs ◽  
Wing Bud ◽  
Tissue Recombination ◽  
Recombination Experiments

Flight is a triumph of evolution that enabled the radiation and success of birds. A crucial step was the development of forelimb flight feathers that may have evolved for courtship or territorial displays in ancestral theropod dinosaurs. Classical tissue recombination experiments performed in the chick embryo provide evidence that signals operating during early limb development specify the position and identity of feathers. Here we show that a positional information gradient of Sonic hedgehog (Shh) signalling in the embryonic chick wing bud specifies the pattern of adult flight feathers in a defined spatial and temporal sequence that reflects their different identities. We reveal that the Shh signalling gradient is interpreted into specific patterns of flight feather-associated gene expression. Our data suggests that flight feather evolution involved the co-option of the pre-existing digit patterning mechanism and therefore uncovers an embryonic process that played a fundamental step in the evolution of avian flight.

scholarly journals The effect of sonic hedgehog on motor neuron positioning in the spinal cord during chicken embryo development

2017 ◽  
Author(s):  
Ciqing Yang ◽  
Xiaoying Li ◽  
Qiuling Li ◽  
Qiong Li ◽  
Han Li ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Motor Neuron ◽  
Embryo Development ◽  
Sonic Hedgehog ◽  
Motor Neurons ◽  
Chicken Embryo ◽  
Positional Information ◽  
Underlying Mechanism ◽  
Correct Location ◽  
Information Cell

ABSTRACTSonic hedgehog (Shh) is a vertebrate homologue of the secreted Drosophila protein hedgehog, and is expressed by the notochord and the floor plate in the developing spinal cord. Shh provides signals relevant for positional information, cell proliferation, and possibly cell survival depending on the time and location of the expression. Although the role of Shh in providing positional information in the neural tube has been experimentally proven, the exact underlying mechanism still remains unclear. In this study, we report that overexpression of Shh affects motor neuron positioning in the spinal cord during chicken embryo development by inducing abnormalities in the structure of the motor column and motor neuron integration. In addition, Shh overexpression inhibits the expression of dorsal transcription factors and commissural axon projections. Our results indicate that correct location of Shh expression is the key to the formation of the motor column. In conclusion, the overexpression of Shh in the spinal cord not only affects the positioning of motor neurons, but also induces abnormalities in the structure of the motor column.

Relationship between retinoic acid and sonic hedgehog, two polarizing signals in the chick wing bud

Development ◽  
1994 ◽  
Vol 120 (11) ◽  
pp. 3267-3274 ◽  
Author(s):  
J. Helms ◽  
C. Thaller ◽  
G. Eichele
Keyword(s):  
Retinoic Acid ◽  
Sonic Hedgehog ◽  
Positional Information ◽  
Limb Bud ◽  
Dependent Manner ◽  
All Trans Retinoic Acid ◽  
Wing Bud ◽  
Zone Of Polarizing Activity ◽  
Dose Dependent

Local application of all-trans-retinoic acid (RA) to the anterior margin of chick limb buds results in pattern duplications reminescent of those that develop after grafting cells from the zone of polarizing activity (ZPA). RA may act directly by conferring positional information to limb bud cells, or it may act indirectly by creating a polarizing region in the tissue distal to the RA source. Here we demonstrate that tissue distal to an RA-releasing bead acquires polarizing activity in a dose-dependent manner. Treatments with pharmacological (beads soaked in 330 micrograms/ml) and physiological (beads soaked in 10 micrograms/ml) doses of RA are equally capable of inducing digit pattern duplication. Additionally, both treatments induce sonic hedgehog (shh; also known as vertebrate hedgehog-1, vhh-1), a putative ZPA morphogen and Hoxd-11, a gene induced by the polarizing signal. However, tissue transplantation assays reveal that pharmacological, but not physiological, doses create a polarizing region. This differential response could be explained if physiological doses induced less shh than pharmacological doses. However, our in situ hybridization analyses demonstrate that both treatments result in similar amounts of mRNA encoding this candidate ZPA morphogen. We outline a model describing the apparently disparate effects of pharmacologic and physiological doses RA on limb bud tissue.

672: Regulation of Cavernous Nerve Injury-Induced Apoptosis by Sonic Hedgehog

2007 ◽  
Vol 177 (4S) ◽  
pp. 225-225
Author(s):  
Carol A. Podlasek ◽  
Yi Tang ◽  
Cynthia L. Meraz ◽  
Kevin E. McKenna ◽  
Kevin T. McVary
Keyword(s):  
Nerve Injury ◽  
Sonic Hedgehog ◽  
Cavernous Nerve ◽  
Induced Apoptosis ◽  
Cavernous Nerve Injury

Crosstalk between Sonic hedgehog and CRH pathways leading to a synergic effect on ACTH secretion

2004 ◽  
Vol 112 (S 1) ◽  
Author(s):  
G Vila ◽  
M Theodoropoulou ◽  
M Papazoglou ◽  
J Stalla ◽  
U Renner ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Synergic Effect ◽  
Acth Secretion
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