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

Parente, Augusto; Topo, Enza; Garcia‐Fernàndez, Jordi; D’Aniello, Salvatore

doi:10.1210/en.2008-1066

Cited by 21 publications

(8 citation statements)

References 32 publications

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“…Another group claimed to have isolated a peptide identical to mammalian GnRH1 from B . lanceolatum , an amphioxus closely related to B. floridae (Chambery et al 2009). This peptide has not been confirmed in the genome by us or others.…”

Section: Discussionmentioning

confidence: 99%

At the Transition from Invertebrates to Vertebrates, a Novel GnRH-Like Peptide Emerges in Amphioxus

Roch

Tello

Sherwood

2013

Molecular Biology and Evolution

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Gonadotropin-releasing hormone (GnRH) is a critical reproductive regulator in vertebrates. Homologous peptides are also found in invertebrates, with a variety of characterized functions. In the amphioxus, an invertebrate that provides the best model for the transition to vertebrates, four GnRH receptors (GnRHRs) were previously described, but their native ligands were not identified. Using a more sensitive search methodology with hidden Markov models, we identified the first GnRH-like peptide confirmed in the amphioxus Branchiostoma floridae. This peptide specifically activated one of the four GnRHRs. Although the primary structure of this peptide was divergent from any previously isolated GnRH peptide, the minimal conserved residues found in all other GnRH superfamily members were retained. The peptide was immunolocalized in proximity of the central canal of the anterior nerve cord, a region where other neuropeptides and receptors have been found. Additionally, the amphioxus GnRH-like gene was positioned in a locus surrounded by syntenic homologs of the human GnRH paralogon. The amphioxus GnRH-like peptide, with its distinct primary structure, activated a receptor with equal potency to multiple ligands that span the GnRH superfamily.

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Section: Discussionmentioning

confidence: 99%

At the Transition from Invertebrates to Vertebrates, a Novel GnRH-Like Peptide Emerges in Amphioxus

Roch

Tello

Sherwood

2013

Molecular Biology and Evolution

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“…If this is indeed the case, a key point of interest would be to elucidate the early evolution of the HPG axis, or more simply, the GnRH-GTHgonadal axis. Indeed, GnRHs, including GnRH-like peptides, have been found not only in chordates including amphioxus (26) and tunicates but also in multiple invertebrate phyla (27). Moreover, amphioxus has a complete set of genes for sex steroid hormone-synthesizing enzymes (17), as well as two genes for steroid hormone receptors, one more closely related to vertebrate estrogen receptors (17).…”

Section: Discussionmentioning

confidence: 99%

Evolutionary origin of a functional gonadotropin in the pituitary of the most primitive vertebrate, hagfish

Uchida

Moriyama

Chiba

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Hagfish, which lack both jaws and vertebrae, are considered the most primitive vertebrate known, living or extinct. Hagfish have long been the enigma of vertebrate evolution not only because of their evolutionary position, but also because of our lack of knowledge on fundamental processes. Key elements of the reproductive endocrine system in hagfish have yet to be elucidated. Here, the presence and identity of a functional glycoprotein hormone (GPH) have been elucidated from the brown hagfish Paramyxine atami. The hagfish GPH consists of two subunits, α and β, which are synthesized and colocalized in the same cells of the adenohypophysis. The cellular and transcriptional activities of hagfish GPHα and -β were significantly correlated with the developmental stages of the gonad. The purified native GPH induced the release of gonadal sex steroids in vitro. From our phylogenetic analysis, we propose that ancestral glycoprotein α-subunit 2 (GPA2) and β-subunit 5 (GPB5) gave rise to GPHα and GPHβ of the vertebrate glycoprotein hormone family, respectively. The identified hagfish GPHα and -β subunits appear to be the typical gnathostome GPHα and -β subunits based on the sequence and phylogenetic analyses. We hypothesize that the identity of a single functional GPH of the hagfish, hagfish GTH, provides critical evidence for the existence of a pituitary-gonadal system in the earliest divergent vertebrate that likely evolved from an ancestral, prevertebrate exclusively neuroendocrine mechanism by gradual emergence of a previously undescribed control level, the pituitary, which is not found in the Protochordates.

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“…For example, gonadotropins were initially reported to be present in amphioxus based on such immunohistochemical studies (e.g., Nozaki & Gorbman, 1992) but were recently shown to be absent from the amphioxus genome like all other adenohypophyseal hormones Putnam et al, 2008). One GnRH peptide previously isolated from amphioxus (Chambery, Parente, Topo, Garcia-Fernandez, & D'Aniello, 2009) could not be confirmed in genomic analyses, but in contrast, another GnRH-like peptide has recently been identified in the amphioxus genome (Roch, Tello, & Sherwood, 2014). Since this peptide activates only one out of four GnRH receptors, additional GnRH peptides are probably present in amphioxus but remain to be identified.…”

Section: Neurosecretory and Sensory Cell Typesmentioning

confidence: 99%

Vertebrate Cranial Placodes as Evolutionary Innovations—The Ancestor's Tale

Schlosser

2015

Current Topics in Developmental Biology

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

Cited by 21 publications

References 32 publications

At the Transition from Invertebrates to Vertebrates, a Novel GnRH-Like Peptide Emerges in Amphioxus

At the Transition from Invertebrates to Vertebrates, a Novel GnRH-Like Peptide Emerges in Amphioxus

Evolutionary origin of a functional gonadotropin in the pituitary of the most primitive vertebrate, hagfish

Vertebrate Cranial Placodes as Evolutionary Innovations—The Ancestor's Tale

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