Immunohistochemical localization of gonadotropin-releasing hormone receptors (GnRHR) in the nervous system, Hatschek’s pit and gonads of amphioxus,Branchiostoma belcheri

Fang, Yue; Huang, Wen‐Chang; Chen, Lei

doi:10.1007/bf02885062

Cited by 7 publications

(4 citation statements)

References 8 publications

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“…In 1999, Fang and collaborators (18) had already reported GnRH immunoreactivity in a variety of neurons in the brain and Hatschek's pit of B. belcheri. Consistent with this, a similar but more accurate work has recently demonstrated the occurrence of GnRH-positive neurons in the amphioxus central nervous system by means of a large set of antisera generated against different GnRH peptides (19).…”

Section: Resultsmentioning

confidence: 97%

“…It is becoming an important model for studies of development and evolution due to its simplified genome and close relationship to vertebrates. To our knowledge, the presence of GnRH/GnRHlike peptides in amphioxus has been reported only after immunohistochemical analysis (18,19) in which the authors reported GnRH presence in the amphioxus nervous system and in the Hatschek's pit. Our aim was 2-fold: first, to ascertain whether or not a peptide with GnRH activity is present in this key animal model, and second, to isolate this peptide to study its evolution at the base of the chordate clade.…”

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confidence: 85%

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Characterization and Putative Role of a Type I Gonadotropin-Releasing Hormone in the Cephalochordate Amphioxus

Parente¹,

Topo

Garcia‐Fernàndez

et al. 2009

Endocrinology

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GnRH, originally isolated from mammalian hypothalamus, is a key player in the control of vertebrate reproduction. Employing reverse-phase chromatography, we purified a peptide of relative molecular mass of 1182.60 Da from the cephalochordate amphioxus Branchiostoma lanceolatum. We found that its amino acid sequence (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH(2)) was identical to that of mammalian GnRH. The highest concentrations (4.04 +/- 0.3 microg/g tissue), localized in the anterior part of the body, occurred in November, a time when amphioxus gonads prepare for the seasonal spawning. Furthermore, the biological activity of amphioxus GnRH was investigated by examining its capability to elicit LH release from the rodent pituitary gland. The origins of GnRH can be traced back to the origins of chordates. The seasonal variations of amphioxus GnRH also suggest an ancient role of this peptide in the control of reproduction in chordates, even before the evolution of a proper pituitary gland.

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Section: Resultsmentioning

confidence: 97%

mentioning

confidence: 85%

Characterization and Putative Role of a Type I Gonadotropin-Releasing Hormone in the Cephalochordate Amphioxus

Parente¹,

Topo

Garcia‐Fernàndez

et al. 2009

Endocrinology

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“…First, several cells immunoreactive for neuropeptides including FMRF amide, neuropeptideY, and GnRH were described in the neural tube and Hatschek's pit of amphioxus (Castro et al, 2003, Chang et al, 1984, Fang et al, 1999, Massari et al, 1999, Nozaki and Gorbman, 1992, but GnRH immunoreactivity in Hatschek's pit could not be confirmed in further studies (Castro et al, 2006a. The presence of many neuropeptides and their G-protein coupled receptors (GPCR) in amphioxus including one GnRH-like peptide and 4 GnRH receptors (two of those related to the vertebrate GnRH receptors) could be confirmed in the amphioxus genome (Holland et al, 2008, Mirabeau and Joly, 2013, Osugi et al, 2016, Putnam et al, 2008.…”

Section: Neurosecretory Cellsmentioning

confidence: 99%

From so simple a beginning – what amphioxus can teach us about placode evolution

Schlosser

2017

Int. J. Dev. Biol.

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Cranial placodes are an evolutionary novelty of vertebrates that give rise to many cranial sense organs and ganglia, as well as to the neurosecretory anterior pituitary. Although amphioxus does not have placodes, it shares with vertebrates several of the ectodermal patterning mechanisms and cell types that are important in placode development. Comparisons between amphioxus, vertebrates and other groups provide us with important insights into what the last common chordate ancestor probably looked like and allow us to propose a scenario for how placodes evolved by rewiring of gene regulatory networks. After reviewing ectodermal patterning and the cytodifferentiation of neurosecretory and sensory cells in amphioxus, this review will argue that the evolutionary origin of cranial placodes involved 1) the concentration of sensory and neurosecretory cell types in the head by linking their development to ancient cranial ectodermal patterning mechanisms; and 2) the formation of high density arrays of sensorineural precursors by intercalating a progenitor expansion module into the gene regulatory network driving differentiation of sensory or neurosecretory cells.

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“…placodes giving rise to the teeth, hair follicles and lens), appear to be lacking in invertebrate chordates. to be immunoreactive for GNRH (Fang et al 1999) and for Pit-1 protein, a transcription factor expressed in the anterior pituitary in vertebrates by Candiani & Pestarino (1998), who suggested that Hatschek's pit is homologous to the adenohypophysis. In addition, in vertebrates, Pax6 and islet1 are expressed in epithelial cells of the developing adenohypophysis (Walther & Gruss, 1991 ;Inoue et al 1994 ;Grindley et al 1995 ;Terzic & Saraga-Babic, 1999).…”

Section: Homology Of the Vertebrate Adenohypophysis With Ascidian Andmentioning

confidence: 99%

Evolution of neural crest and placodes: amphioxus as a model for the ancestral vertebrate?

Holland

2001

Journal of Anatomy

141

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Recent studies of protochordates (ascidian tunicates and amphioxus) have given insights into possible ancestors of 2 of the characteristic features of the vertebrate head: neural crest and placodes. The neural crest probably evolved from cells on either side of the neural plate-epidermis boundary in a protochordate ancestral to the vertebrates. In amphioxus, homologues of several vertebrate neural crest marker genes (BMP2/4, Pax3/7, Msx, Dll and Snail) are expressed at the edges of the neural plate and/or adjacent nonneural ectoderm. Some of these markers are also similarly expressed in tunicates. In protochordates, however, these cells, unlike vertebrate neural crest, neither migrate as individuals through embryonic tissues nor differentiate into a wide spectrum of cell types. Therefore, while the protochordate ancestor of the vertebrates probably had the beginnings of a genetic programme for neural crest formation, this programme was augmented in the earliest vertebrates to attain definitive neural crest. Clear homologues of vertebrate placodes are lacking in protochordates. However, both amphioxus and tunicates have ectodermal sensory cells. In tunicates these are all primary neurons, sending axons to the central nervous system, while in amphioxus, the ectodermal sensory cells include both primary neurons and secondary neurons lacking axons. Comparisons of developmental gene expression suggest that the anterior ectoderm in amphioxus may be homologous to the vertebrate olfactory placode, the only vertebrate placode with primary, not secondary, neurons. Similarly, biochemical, morphological and gene expression data suggest that amphioxus and tunicates also have homologues of the adenohypophysis, one of the few vertebrate structures derived from nonneurogenic placodes. In contrast, the origin of the other vertebrate placodes is very uncertain.

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Immunohistochemical localization of gonadotropin-releasing hormone receptors (GnRHR) in the nervous system, Hatschek’s pit and gonads of amphioxus,Branchiostoma belcheri

Cited by 7 publications

References 8 publications

Characterization and Putative Role of a Type I Gonadotropin-Releasing Hormone in the Cephalochordate Amphioxus

Characterization and Putative Role of a Type I Gonadotropin-Releasing Hormone in the Cephalochordate Amphioxus

From so simple a beginning – what amphioxus can teach us about placode evolution

Evolution of neural crest and placodes: amphioxus as a model for the ancestral vertebrate?

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