Molecular cloning and differential expression of three GnRH mRNAs in discrete brain areas and lymphocytes in red drum

Mohamed, Junaith S.; Khan, Izhar Ahmad

doi:10.1677/joe.1.06423

Cited by 21 publications

(11 citation statements)

References 33 publications

(47 reference statements)

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“…In this species, in addition to the prominent pre-optic neurones projecting to the pituitary, GnRH1 is expressed in the neurones in the olfactory bulb, ventral telencephalon and ventrolateral hypothalamus. 5) (Okubo et al 2006, unpublished data) and red drum Sciaenops ocellatus (Mohamed & Khan 2006). Hence, the distribution of the GnRH1-and GnRH3-expressing neurones overlaps in the forebrain.…”

Section: Subfunctionalization Of Three Paralogous Genes For Gnrhmentioning

confidence: 97%

“…Since then, the possible occurrence of multiple forms of GnRH in vertebrates has been a focus of investigation, and two different forms have been identified in a number of species, including several mammals (Kasten et al 1996, Lescheid et al 1997, Urbanski et al 1999). Furthermore, three distinct forms of GnRH have been demonstrated in more than 20 teleost species (Powell et al 1994, Weber et al 1997, Carolsfeld et al 2000, Okubo et al 2000, Andersson et al 2001, Montaner et al 2001, Adams et al 2002, Amano et al 2002a, Somoza et al 2002, Zmora et al 2002, Ikemoto & Park 2005, Mohamed et al 2005, Mohamed & Khan 2006, Hajdu et al 2007). The occurrence of three forms of GnRH in these teleosts suggested that three distinct paralogous GnRH genes exist in the vertebrate lineage.…”

Section: Molecular Forms Of Gnrh and Their Genes In Vertebratesmentioning

confidence: 99%

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Structural and functional evolution of gonadotropin‐releasing hormone in vertebrates

2008

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The neuropeptide gonadotropin-releasing hormone (GnRH) has a central role in the neural control of vertebrate reproduction. This review describes an overview of what is currently known about GnRH in vertebrates in the context of its structural and functional evolution. A large body of evidence has demonstrated the existence of three paralogous genes for GnRH (GnRH1, GnRH2 and GnRH3) in the vertebrate lineage. They are most probably the products of whole-genome duplications that occurred early in vertebrate evolution. Although GnRH3 has been identified only in teleosts, comparative genomic analyses indicated that GnRH3 has not arisen from a teleost-specific genome duplication, but has been derived from an earlier genome duplication in an ancestral vertebrate, followed by its loss in the tetrapod lineage. A loss of other paralogous genes has also occurred independently in different vertebrate lineages, leading to species-specific differences in the organization of the GnRH system. In addition to the GnRH3 gene, the GnRH2 gene has been deleted or silenced in certain mammalian species, while some teleosts seem to have lost the GnRH1 or GnRH3 gene. The duplicated GnRH genes have undergone subfunctionalization during the evolution of vertebrates; GnRH1 has become the major stimulator of gonadotropins and probably other pituitary hormones as well, whereas GnRH2 and GnRH3 would have functioned as neuromodulators, affecting reproductive behaviour. Conversely, in cases where a paralogous gene for GnRH has been lost, one of the remaining paralogues appears to have adopted its role.

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Section: Subfunctionalization Of Three Paralogous Genes For Gnrhmentioning

confidence: 97%

Section: Molecular Forms Of Gnrh and Their Genes In Vertebratesmentioning

confidence: 99%

Structural and functional evolution of gonadotropin‐releasing hormone in vertebrates

2008

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“…However, not all teleosts with three types of GnRH have this distinction between GnRH forms. Some species have overlapping distributions of GnRH1‐ and GnRH3‐producing neurons in the hypothalamus and olfactory bulb (Gonzalez‐Martinez et al , 2002 a ; Vickers et al , 2004; Mohamed et al , 2005; Pandolfi et al , 2005; Mohamed & Khan, 2006). Interestingly, both GnRH1 and GnRH3 neurons arise in the olfactory placode and migrate to their final positions during development (Sullivan & Silverman, 1993; Yoshida et al , 1995; White & Fernald, 1998 b ; Amano et al , 2002 b ; Gonzalez‐Martinez et al , 2002 b ; Whitlock et al , 2003; Okubo et al , 2006; Palevitch et al , 2007), suggesting that GnRH1 and GnRH3 may be derived from a gene duplication; this notion also supported by phylogenetic evidence.…”

Section: Gnrh1 and Gnrh3 Share An Ancestormentioning

confidence: 99%

GnRH and GnRH receptors: distribution, function and evolution

Chen

Fernald

2008

Journal of Fish Biology

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Gonadotropin-releasing hormone (GnRH) was originally identified because of its essential role in regulating reproduction in all vertebrates. Since then, three phylogenetically related GnRH decapeptides have been characterized in vertebrates and invertebrates. Almost all tetrapods investigated have at least two GnRH forms (GnRH1 and GnRH2) in the central nervous system. From distributional and functional studies in vertebrates, GnRH1 in the hypothalamus projects predominantly to the pituitary and regulates reproduction via gonadotropin release. GnRH2, which is located in the midbrain, projects to the whole brain and is thought to be involved in sexual behaviour and food intake. GnRH3, located in the forebrain, has only been found in teleost fish and appears to be involved in sexual behaviour, as well as, in some fish species, gonadotropin release. Multiple GnRH receptors (GnRH-Rs), G-protein-coupled receptors regulate endocrine functions and neural transmissions in vertebrates. Phylogenetic and structural analyses of coding sequences show that all vertebrate GnRH-Rs cluster into two main receptor types comprised of four subfamilies. This suggests that at least two rounds of GnRH receptor gene duplications may have occurred in different groups within each lineage. Functional studies suggest that two particular subfamilies of GnRH receptors have independently evolved to act as species-specific endocrine modulators in the pituitary, and these show the greatest variety in regulating neuron networks in the brain. Given the long evolutionary history of the GnRH system, it seems likely that much more remains to be understood about its roles in behaviour and function of vertebrates.

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“…seabream or whitefish GnRH (GnRH-I), chicken GnRH-II (GnRH-II), and salmon GnRH (GnRH-III). Differential distribution of the three forms of GnRH has been studied in the brains of several species belonging to the order Perciformes (White et al 1995, González-Martínez et al 2001, Vickers et al 2004, Mohamed et al 2005, Mohamed & Khan 2006. In addition, the GnRH-I and GnRH-III neuronal elements have been shown to overlap in certain anterior forebrain regions, including the preoptic area (POA) of European seabass, Atlantic croaker and red drum (González-Martínez et al 2001, Mohamed et al 2005, Mohamed & Khan 2006.…”

Section: Introductionmentioning

confidence: 99%

“…Differential distribution of the three forms of GnRH has been studied in the brains of several species belonging to the order Perciformes (White et al 1995, González-Martínez et al 2001, Vickers et al 2004, Mohamed et al 2005, Mohamed & Khan 2006. In addition, the GnRH-I and GnRH-III neuronal elements have been shown to overlap in certain anterior forebrain regions, including the preoptic area (POA) of European seabass, Atlantic croaker and red drum (González-Martínez et al 2001, Mohamed et al 2005, Mohamed & Khan 2006. The POA GnRH-I is considered the major hypophysiotropic hormone that controls the synthesis and release of follicle stimulating hormone (FSH) and LH in all vertebrates, and GnRH-I neurons have been shown to innervate the anterior pituitary in teleosts (Gothilf et al 1997, Amano et al 2002, González-Martínez et al 2002.…”

Section: Introductionmentioning

confidence: 99%

Developmental expression of the G protein-coupled receptor 54 and three GnRH mRNAs in the teleost fish cobia

Mohamed¹,

Benninghoff²,

Holt³

et al. 2007

Journal of Molecular Endocrinology

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The cDNAs of the G protein-coupled receptor 54 (GPR54) and three prepro-gonadotropin-releasing hormones, GnRH-I (seabream GnRH), GnRH-II (chicken GnRH-II), and GnRH-III (salmon GnRH) were isolated and cloned from the brain of the teleost fish cobia, Rachycentron canadum. The cobia GPR54 cDNA was 95 and 51-56% identical to those of tilapia and mammalian models respectively. The GnRH cDNA sequences of cobia showed strong identities to those of tilapia, Atlantic croaker, red drum, and the seabass and seabream species. The real-time quantitative RT-PCR methods allowed detection of all three GnRH mRNAs on the first day after hatching (DAH). The GnRH-I mRNA levels, which were the lowest among the three GnRHs, increased gradually with two distinct peaks in larvae at 3 and 4 DAH. On the other hand, GnRH-II and GnRH-III mRNAs were significantly higher in larvae at 2 and 6 DAH compared with those on the preceding days. In addition, significant peaks of all the three GnRH mRNAs were observed in the brains of 26-day-old fish. The finding of higher GnRH-I and GnRH-II mRNAs in males than females at 153 DAH may be related to early puberty observed during the first year in laboratory-reared male cobia. Moreover, this study demonstrates for the first time the expression of GPR54 mRNA during larval development in a vertebrate species. The concomitant expression patterns of GPR54 and GnRH mRNAs during different stages of larval and juvenile developments, and during early puberty in male cobia suggest a potential relationship between GPR54 and multiple GnRHs during these stages of development consistent with the role of GPR54 in controlling GnRH release in mammals. The increase in GPR54 and GnRH mRNAs observed during early puberty in cobia is consistent with a similar change reported in pubertal rats. This finding together with the localization of GPR54 mRNAs on GnRH neurons in fish and mammals suggests that the GPR54-GnRH interactions may be conserved in different vertebrate groups.

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Molecular cloning and differential expression of three GnRH mRNAs in discrete brain areas and lymphocytes in red drum

Cited by 21 publications

References 33 publications

Structural and functional evolution of gonadotropin‐releasing hormone in vertebrates

Structural and functional evolution of gonadotropin‐releasing hormone in vertebrates

GnRH and GnRH receptors: distribution, function and evolution

Developmental expression of the G protein-coupled receptor 54 and three GnRH mRNAs in the teleost fish cobia

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