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Russell D. Fernald - One of the best experts on this subject based on the ideXlab platform.
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A behavioral logic underlying aggression in an African cichlid fish
2020Co-Authors: Beau A. Alward, Phillip H. Cathers, Danielle Blakkan, Russell D. FernaldAbstract:Social rank in a hierarchy determines which individuals have access to important resources such as food, shelter, and mates. In the African cichlid fish Astatotilapia burtoni, rank is under social control, such that larger males are more likely than smaller males to be dominant in rank. Although it is well known that the relative size of A. burtoni males is critical in controlling social rank, the specific behavioral strategies underlying responses to males of different sizes are not well understood. In this research, our goal was to characterize these responses by performing resident-intruder assays, in which aggressive behaviors were measured in territorial males in response to the introduction of unfamiliar males that differed in relative standard length (SL). We found that the relative SL of intruders played an important role in determining behavioral performance. Resident males exposed to larger (>5% larger in SL) or matched (between 0 and 5% larger or smaller in SL) intruder males performed more lateral displays, a type of non-physical aggression, compared to resident males exposed to smaller (>5% smaller in SL) intruder males. However, physical aggression, such as chases and bites, did not differ as a function of relative SL. Our results suggest that A. burtoni males amplify non-physical aggression to settle territorial disputes in response to differences in relative SL that were not previously considered to be behaviorally relevant. HighlightsO_LIRelative size determines social rank in the African cichlid Astatotilapia burtoni C_LIO_LIResident male A. burtoni respond differently to small size differences in intruder males C_LIO_LIResidents perform more non-physical aggression against larger intruders C_LIO_LIResidents do not alter physical aggression as a function of differently sized intruders C_LIO_LIDistinct behavioral strategies are used against different intruders C_LI
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Modular genetic control of social status in a cichlid fish
2020Co-Authors: Beau A. Alward, Scott A. Juntti, Vibhav A. Laud, Christopher J. Skalnik, Ryan A. York, Russell D. FernaldAbstract:Social hierarchies are ubiquitous in social species, yet the mechanisms underlying social status are unclear. In the African cichlid fish Astatotilapia burtoni, males stratify along a dominance hierarchy that varies based on testes mass, coloration, and behavior. Using androgen receptor (AR) mutant A. burtoni generated using CRISPR/Cas9, we find that two AR genes control social dominance. ARβ, but not ARα, is required for testes growth and bright coloration, while ARα, but not ARβ, is required for the performance of reproductive behavior and aggressive displays. Neither receptor is required for attacking males. Analysis of AR double mutants revealed that either AR is sufficient for attacking males. Social status in A. burtoni males is modularly controlled by ARα and ARβ, indicating that these genes have undergone subfunctionalization.
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Astatotilapia burtoni: A Model System for Analyzing the Neurobiology of Behavior
ACS chemical neuroscience, 2018Co-Authors: Karen P. Maruska, Russell D. FernaldAbstract:Most biomedical research is performed using a very limited number of “model” species. In part, this has resulted from a combination of full genomes, manipulation of genes, and short generation times in these species. However, the advent of low-cost sequencing and gene editing in any organism has increased the use of nontraditional organisms. Many scientists have paraphrased the adage by Krogh [Krogh, A. (2018) Science 70, 200−204] that for many biological problems some species will prove to be most convenient and useful to study. In particular, using organisms most suited to the specific research question can lead to novel insights about fundamental physiological, neurobiological, immunological, and neuroendocrine systems that can advance our understanding of the well-being and health of humans. In addition, such studies have led to new ideas about the evolution and mechanisms that control social behavior. Fishes constitute about 50% of all vertebrate species and are the most diverse vertebrate radiation....
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Polygenic sex determination in the cichlid fish Astatotilapia burtoni.
BMC genomics, 2016Co-Authors: Natalie B. Roberts, Russell D. Fernald, Scott A. Juntti, Kaitlin P. Coyle, Beth L. Dumont, M. Kaitlyn Stanley, Allyson Q. Ryan, Reade B. RobertsAbstract:The East African riverine cichlid species Astatotilapia burtoni serves as an important laboratory model for sexually dimorphic physiology and behavior, and also serves as an outgroup species for the explosive adaptive radiations of cichlid species in Lake Malawi and Lake Victoria. An astounding diversity of genetic sex determination systems have been revealed within the adaptive radiation of East African cichlids thus far, including polygenic sex determination systems involving the epistatic interaction of multiple, independently segregating sex determination alleles. However, sex determination has remained unmapped in A. burtoni. Here we present mapping results supporting the presence of multiple, novel sex determination alleles, and thus the presence of polygenic sex determination in A. burtoni. Using mapping in small families in conjunction with restriction-site associated DNA sequencing strategies, we identify associations with sex at loci on linkage group 13 and linkage group 5–14. Inheritance patterns support an XY sex determination system on linkage group 5–14 (a chromosome fusion relative to other cichlids studied), and an XYW system on linkage group 13, and these associations are replicated in multiple families. Additionally, combining our genetic data with comparative genomic analysis identifies another fusion that is unassociated with sex, with linkage group 8–24 and linkage group 16–21 fused in A. burtoni relative to other East African cichlid species. We identify genetic signals supporting the presence of three previously unidentified sex determination alleles at two loci in the species A. burtoni, strongly supporting the presence of polygenic sex determination system in the species. These results provide a foundation for future mapping of multiple sex determination genes and their interactions. A better understanding of sex determination in A. burtoni provides important context for their use in behavioral studies, as well as studies of the evolution of genetic sex determination and sexual conflicts in East African cichlids.
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Subject: Psychology, Neuropsychology Online Publication Date: Apr 2014 DOI: 10.1093/oxfordhb/9780199753888.013.012 Social Regulation of Gene Expression in the African Cichlid Fish Astatotilapia burtoni
2016Co-Authors: Karen P. Maruska, Russell D. FernaldAbstract:How does an animal’s social environment shape its behavior and physiology, and what underlying molecular and genetic mechanisms lead to phenotypic changes? To address this question, the authors used a model system that exhibits socially regulated plastic phenotypes, behavioral complexity, molecular level access, and genomic resources. The African cichlid fish Astatotilapia burtoni, in which male status and reproductive physiology are under social control, has become an important model for studying the mechanisms that regulate complex social behaviors. This chapter reviews what is known about how information from the social environment produces changes in behavior, physiology, and gene expression profiles in the brain and reproductive axis of A. burtoni. Understanding the mechanisms responsible for translating perception of social cues into molecular change in a model vertebrate is important for identifying selective pressures and evolutionary mechanisms that shape the brain and ultimately result in diverse and complex social behaviors
Hans A. Hofmann - One of the best experts on this subject based on the ideXlab platform.
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Equal performance but distinct behaviors: Astatotilapia burtoni sex differences in a novel object recognition task and spatial maze
2020Co-Authors: Kelly J Wallace, Hans A. HofmannAbstract:Sex differences in behavior and cognition can be driven by differential selection pressures from the environment and in the underlying neuromolecular mechanisms of decision-making. The highly social cichlid fish Astatotilapia burtoni exhibits dynamic and complex social hierarchies, yet explicit cognitive testing (outside of social contexts) and investigations of sex differences in cognition have yet to be fully explored. Here we assessed male and female A. burtoni in two cognitive tasks: a novel object recognition task and a spatial task. We hypothesized that given both males and females navigate dynamic social environments, we would observe less pronounced sex differences in cognition relative to other species with more "static" sex differences. In the present study we find that both sexes prefer the familiar object in a novel object recognition task, but the time at which they exhibit this preference differs between the sexes. Females more frequently learned a spatial task, exhibiting longer decision latencies and quicker error correction, suggesting a potential speed-accuracy tradeoff. Furthermore, the sexes differ in space use in both tasks and in a principal component analysis of the spatial task. A model selection analysis finds that preference, approach, and interaction duration in the novel object recognition task that reach a threshold of importance averaged across all models. This work highlights the need to explicitly test for sex differences in cognition to better understand how individuals navigate dynamic social environments. Highlights- To ask if sexual dimorphism in cognition is reduced in a species where both sexes navigate highly fluctuating social environments, we assessed performance and behavior of the cichlid fish Astatotilapia burtoni in a novel object recognition task and a spatial maze. - Both sexes exhibited a preference for the familiar object during a novel object recognition task, with males exhibiting the preference early in the task, whereas females exhibiting the preference late in the task. - In the spatial task, females reached the learning criterion more often than expected by chance, whereas males do not. Females exhibited significantly longer decision latencies and quicker error correction in the spatial task, suggesting a sex-specific speed-accuracy tradeoff. - The sexes differ in behaviors related to neophobia and decision latencies. - A model selection analysis to predict sex finds that novel object recognition task preference, approach, and interaction duration are the most important terms on average.
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Supplemental Material and Method from The melanocortin system regulates body pigmentation and social behaviour in a colour polymorphic cichlid fish†
2017Co-Authors: Peter D. Dijkstra, Sean M. Maguire, Rayna M. Harris, Agosto A. Rodriguez, Ross S. Deangelis, Stephanie A. Flores, Hans A. HofmannAbstract:The melanocortin system is a neuroendocrine system that regulates a range of physiological and behavioural processes. We examined the extent to which the melanocortin system simultaneously regulates colour and behaviour in the cichlid fish Astatotilapia burtoni. We found that yellow males are more aggressive than blue males, in line with previous studies. We then found that exogenous α-melanocyte-stimulating hormone (α-MSH) increases yellowness of the body and dispersal of xanthophore pigments in both morphs. However, α-MSH had a morph-specific effect on aggression, with only blue males showing an increase in the rate of aggression. Exogenous agouti signalling peptide (ASIP), a melanocortin antagonist, did not affect coloration but reduced the rate of aggression in both colour morphs. Blue males had higher cortisol levels than yellow males. Neural gene expression of melanocortin receptors (mcr) and ligands was not differentially regulated between colour morphs. In the skin, however, mc1r and pro-opiomelanocortin (pomc) β were upregulated in blue males, while asip 1 was upregulated in yellow males. The effects of α-MSH on behaviour and body coloration, combined with morph-specific regulation of the stress response and the melanocortin system, suggest that the melanocortin system contributes to the polymorphism in behaviour and coloration in A. burtoni
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Supplemental Results from The melanocortin system regulates body pigmentation and social behaviour in a colour polymorphic cichlid fish†
2017Co-Authors: Peter D. Dijkstra, Sean M. Maguire, Rayna M. Harris, Agosto A. Rodriguez, Ross S. Deangelis, Stephanie A. Flores, Hans A. HofmannAbstract:The melanocortin system is a neuroendocrine system that regulates a range of physiological and behavioural processes. We examined the extent to which the melanocortin system simultaneously regulates colour and behaviour in the cichlid fish Astatotilapia burtoni. We found that yellow males are more aggressive than blue males, in line with previous studies. We then found that exogenous α-melanocyte-stimulating hormone (α-MSH) increases yellowness of the body and dispersal of xanthophore pigments in both morphs. However, α-MSH had a morph-specific effect on aggression, with only blue males showing an increase in the rate of aggression. Exogenous agouti signalling peptide (ASIP), a melanocortin antagonist, did not affect coloration but reduced the rate of aggression in both colour morphs. Blue males had higher cortisol levels than yellow males. Neural gene expression of melanocortin receptors (mcr) and ligands was not differentially regulated between colour morphs. In the skin, however, mc1r and pro-opiomelanocortin (pomc) β were upregulated in blue males, while asip 1 was upregulated in yellow males. The effects of α-MSH on behaviour and body coloration, combined with morph-specific regulation of the stress response and the melanocortin system, suggest that the melanocortin system contributes to the polymorphism in behaviour and coloration in A. burtoni
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Arginine vasotocin regulates social ascent in the African cichlid fish Astatotilapia burtoni.
General and comparative endocrinology, 2014Co-Authors: Lin S. Huffman, Flora I. Hinz, Sophie Wojcik, Nadia Aubin-horth, Hans A. HofmannAbstract:Neuropeptides modulate many aspects of behavior and physiology in a broad range of animals. Arginine vasotocin (AVT) is implicated in mediating social behavior in teleost fish, although its specific role varies between species, sexes, life stages, and social context. To investigate whether the effects of AVT on behavior depend on social context, we used the African cichlid fish Astatotilapia burtoni, which is well-known for its remarkable behavioral plasticity. We pharmacologically manipulated the AVT system in established socially dominant and subordinate A. burtoni males, as well as in males ascending to dominance status in a socially unstable environment. Our results show that exogenous AVT causes a stress response, as evidenced by reduced behavioral activity and increased circulating levels of cortisol in established dominant and subordinate males. Administration of the AVT antagonist Manning compound, on the other hand, did not affect established subordinate or dominant males. However, AVT antagonist-treated males ascending from subordinate to dominant status exhibited reduced aggressive and increased courtship behavior compared to vehicle-treated animals. Finally, we measured circulating cortisol levels and brain gene expression levels of AVT and its behaviorally relevant V1a2 receptor in all three social phenotypes and found that plasma cortisol and mRNA levels of both genes were increased in ascending males compared to dominant and subordinate males. Our results provide a more detailed understanding of the role of the AVT system in the regulation of complex behavior in a dynamically changing social environment.
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Aromatase regulates aggression in the African cichlid fish Astatotilapia burtoni.
Physiology & Behavior, 2013Co-Authors: Lin S. Huffman, Lauren A. O’connell, Hans A. HofmannAbstract:The roles of estrogen and androgens in male social behavior are well studied, but little is known about how these hormones contribute to behavior in a social hierarchy. Here we test the role of aromatase, the enzyme that converts testosterone into estradiol, in mediating aggression and reproductive behavior in male Astatotilapia burtoni, an African cichlid fish that displays remarkable plasticity in social behavior. We first measured aromatase expression in subordinate and dominant males in brain regions that regulate social behavior and found that subordinate males have higher aromatase expression than dominant males in the magnocellular and gigantocellular regions of the preoptic area. Next, we functionally tested the role of aromatase in regulating behavior by intraperitoneally injecting dominant males with either saline or fadrozole (FAD), an aromatase inhibitor, and found that FAD treatment decreases aggressive, but not reproductive, behaviors compared to saline controls. To determine the underlying physiological and molecular consequences of FAD treatment, we measured estradiol and testosterone levels from plasma and brain aromatase expression in FAD and saline treated dominant males. We found that estradiol levels decreased and testosterone levels increased in response to FAD treatment. Moreover, FAD treated males had increased aromatase expression in the gigantocellular portion of the POA, possibly a compensatory response. Overall, our results suggest aromatase is a key enzyme that promotes aggression in A. burtoni males through actions in the preoptic area.
Karen P. Maruska - One of the best experts on this subject based on the ideXlab platform.
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opsin expression varies with reproductive state in the cichlid fish Astatotilapia burtoni
Integrative and Comparative Biology, 2021Co-Authors: Julie M Butler, Karen P. MaruskaAbstract:Animals use visual communication to convey crucial information about their identity, reproductive status, and sex. Plasticity in the auditory and olfactory systems has been well-documented, however, fewer studies have tested for plasticity in the visual system, a surprising detail since courtship and mate choice are largely dependent on visual signals across taxa. We previously found reproductive state-dependent plasticity in the eye of the highly social cichlid fish Astatotilapia burtoni. Male A. burtoni increase their courtship, including multicomponent visual displays, when around ovulated females, and ovulated females are more responsive to male visual courtship displays than non-ovulated females. Based on this, we hypothesized that ovulation status impacts visual capabilities in A. burtoni females. Using electroretinograms, we found that ovulated females had greater visual sensitivity at wavelengths corresponding to male courtship coloration compared to non-reproductively-receptive females. In addition, ovulated females had higher neural activation in the retina and higher mRNA expression levels of neuromodulatory receptors (e.g sex-steroids; gonadotropins) in the eye than non-ovulated females. Here, we add to this body of work by testing the hypothesis that cone opsin expression changes with female reproductive state. Ovulated females had higher expression of short wavelength sensitive opsins (sws1, sws2a, sws2b) compared to mouthbrooding females. Further, expression of sws2a, the most abundant opsin in the A. burtoni eye, positively correlated with levels of circulating 11-ketotestosterone and estradiol and estrogen, androgen, and gonadotropin system receptor expression in the eye in females. These data indicate that reproductive state-dependent plasticity also occurs at the level of photoreceptors, not just through modulation of visual signals at downstream retinal layers. Collectively, these data provide crucial evidence linking endocrine modulation of visual plasticity to mate choice behaviors in females.
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Astatotilapia burtoni: A Model System for Analyzing the Neurobiology of Behavior
ACS chemical neuroscience, 2018Co-Authors: Karen P. Maruska, Russell D. FernaldAbstract:Most biomedical research is performed using a very limited number of “model” species. In part, this has resulted from a combination of full genomes, manipulation of genes, and short generation times in these species. However, the advent of low-cost sequencing and gene editing in any organism has increased the use of nontraditional organisms. Many scientists have paraphrased the adage by Krogh [Krogh, A. (2018) Science 70, 200−204] that for many biological problems some species will prove to be most convenient and useful to study. In particular, using organisms most suited to the specific research question can lead to novel insights about fundamental physiological, neurobiological, immunological, and neuroendocrine systems that can advance our understanding of the well-being and health of humans. In addition, such studies have led to new ideas about the evolution and mechanisms that control social behavior. Fishes constitute about 50% of all vertebrate species and are the most diverse vertebrate radiation....
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swim bladder morphology changes with female reproductive state in the mouth brooding african cichlid Astatotilapia burtoni
The Journal of Experimental Biology, 2017Co-Authors: Julie M Butler, Sarah M Whitlow, Anwei P Gwan, Prosanta Chakrabarty, Karen P. MaruskaAbstract:ABSTRACT Mouth brooding is an extreme form of parental care in which the brooding parent carries the developing young in their buccal cavity for the duration of development. Brooding fish need to compensate for the brood weight on the anterior portion of their body. For fishes with a compartmentalized swim bladder, gas distribution between the chambers may aid in regulating buoyancy during brooding. To test this hypothesis, we took radiographs of Astatotilapia burtoni to compare the swim bladder morphology of gravid, mouth-brooding and recovering females. Following spawning, females carry developing fish in their buccal cavity for ∼2 weeks, resulting in a larger and rounder anterior swim bladder compartment. Comparatively, the swim bladder of gravid females is long and cylindrical. Using small beads to mimic brood weight and its effects on female buoyancy, swim bladder changes were induced that resembled those observed during brooding. Immediately after releasing their fry, brooding females swim at a positive angle of attack but correct their swimming posture to normal within 5 min, suggesting a rapid change in swim bladder gas distribution. These data provide new insights into how swim bladder morphology and swimming behavior change during mouth brooding, and suggest a compartmentalized swim bladder may be a morphological adaptation for mouth brooding.
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Subject: Psychology, Neuropsychology Online Publication Date: Apr 2014 DOI: 10.1093/oxfordhb/9780199753888.013.012 Social Regulation of Gene Expression in the African Cichlid Fish Astatotilapia burtoni
2016Co-Authors: Karen P. Maruska, Russell D. FernaldAbstract:How does an animal’s social environment shape its behavior and physiology, and what underlying molecular and genetic mechanisms lead to phenotypic changes? To address this question, the authors used a model system that exhibits socially regulated plastic phenotypes, behavioral complexity, molecular level access, and genomic resources. The African cichlid fish Astatotilapia burtoni, in which male status and reproductive physiology are under social control, has become an important model for studying the mechanisms that regulate complex social behaviors. This chapter reviews what is known about how information from the social environment produces changes in behavior, physiology, and gene expression profiles in the brain and reproductive axis of A. burtoni. Understanding the mechanisms responsible for translating perception of social cues into molecular change in a model vertebrate is important for identifying selective pressures and evolutionary mechanisms that shape the brain and ultimately result in diverse and complex social behaviors
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Identification of prohormones and pituitary neuropeptides in the African cichlid, Astatotilapia burtoni
BMC genomics, 2016Co-Authors: Bruce R. Southey, Jonathan V. Sweedler, Karen P. Maruska, Elena V. Romanova, Russell D. FernaldAbstract:Background Cichlid fishes have evolved remarkably diverse reproductive, social, and feeding behaviors. Cell-to-cell signaling molecules, notably neuropeptides and peptide hormones, are known to regulate these behaviors across vertebrates. This class of signaling molecules derives from prohormone genes that have undergone multiple duplications and losses in fishes. Whether and how subfunctionalization, neofunctionalization, or losses of neuropeptides and peptide hormones have contributed to fish behavioral diversity is largely unknown. Information on fish prohormones has been limited and is complicated by the whole genome duplication of the teleost ancestor. We combined bioinformatics, mass spectrometry-enabled peptidomics, and molecular techniques to identify the suite of neuropeptide prohormones and pituitary peptide products in Astatotilapia burtoni, a well-studied member of the diverse African cichlid clade.
Lauren A. Munchrath - One of the best experts on this subject based on the ideXlab platform.
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Distribution of sex steroid hormone receptors in the brain of an African cichlid fish, Astatotilapia burtoni
The Journal of comparative neurology, 2010Co-Authors: Lauren A. Munchrath, Hans A. HofmannAbstract:Sex steroid hormones released from the gonads play an important role in mediating social behavior across all vertebrates. Many effects of these gonadal hormones are mediated by nuclear steroid hormone receptors, which are crucial for integration in the brain of external (e.g., social) signals with internal physiological cues to produce an appropriate behavioral output. The African cichlid fish Astatotilapia burtoni presents an attractive model system for the study of how internal cues and external social signals are integrated in the brain as males display robust plasticity in the form of two distinct, yet reversible, behavioral and physiological phenotypes depending on the social environment. In order to better understand where sex steroid hormones act to regulate social behavior in this species, we have determined the distribution of the androgen receptor, estrogen receptor alpha, estrogen receptor beta, and progesterone receptor mRNA and protein throughout the telencephalon and diencephalon and some mesencephalic structures of A. burtoni. All steroid hormone receptors were found in key brain regions known to modulate social behavior in other vertebrates including the proposed teleost homologs of the mammalian amygdalar complex, hippocampus, striatum, preoptic area, anterior hypothalamus, ventromedial hypothalamus, and ventral tegmental area. Overall, there is high concordance of mRNA and protein labeling. Our results significantly extend our understanding of sex steroid pathways in the cichlid brain and support the important role of nuclear sex steroid hormone receptors in modulating social behaviors in teleosts and across vertebrates.
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distribution of sex steroid hormone receptors in the brain of an african cichlid fish Astatotilapia burtoni
The Journal of Comparative Neurology, 2010Co-Authors: Lauren A. Munchrath, Hans A. HofmannAbstract:Sex steroid hormones released from the gonads play an important role in mediating social behavior across all vertebrates. Many effects of these gonadal hormones are mediated by nuclear steroid hormone receptors, which are crucial for integration in the brain of external (e.g., social) signals with internal physiological cues to produce an appropriate behavioral output. The African cichlid fish Astatotilapia burtoni presents an attractive model system for the study of how internal cues and external social signals are integrated in the brain as males display robust plasticity in the form of two distinct, yet reversible, behavioral and physiological phenotypes depending on the social environment. In order to better understand where sex steroid hormones act to regulate social behavior in this species, we have determined the distribution of the androgen receptor, estrogen receptor alpha, estrogen receptor beta, and progesterone receptor mRNA and protein throughout the telencephalon and diencephalon and some mesencephalic structures of A. burtoni. All steroid hormone receptors were found in key brain regions known to modulate social behavior in other vertebrates including the proposed teleost homologs of the mammalian amygdalar complex, hippocampus, striatum, preoptic area, anterior hypothalamus, ventromedial hypothalamus, and ventral tegmental area. Overall, there is high concordance of mRNA and protein labeling. Our results significantly extend our understanding of sex steroid pathways in the cichlid brain and support the important role of nuclear sex steroid hormone receptors in modulating social behaviors in teleosts and across vertebrates. J. Comp. Neurol. 518:3302‐3326, 2010.
Nicola Illing - One of the best experts on this subject based on the ideXlab platform.
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Expression, Structure, Function, and Evolution of Gonadotropin-Releasing Hormone (GnRH) Receptors GnRH-R1SHS and GnRH-R2PEY in the Teleost,
2015Co-Authors: Astatotilapia Burtoni, Russell D. Fernald, Colleen A. Flanagan, Chun-chun Chen, Marla Coetsee, Sipho Mamputha, Kathleen E. Whitlock, Nicholas Bredenkamp, Logan Grosenick, Nicola IllingAbstract:Multiple GnRH receptors are known to exist in nonmamma-lian species, but it is uncertain which receptor type regulates reproduction via the hypothalamic-pituitary-gonadal axis. The teleost fish,Astatotilapia burtoni, is useful for identifying the GnRH receptor responsible for reproduction, because only territorial males reproduce. We have cloned a second GnRH receptor in A. burtoni, GnRH-R1SHS (SHS is a peptide motif in extracellular loop 3), which is up-regulated in pitu-itaries of territorial males. We have shown that GnRH-R1SHS is expressed in many tissues and specifically colocalizes with LH in the pituitary. In A. burtoni brain, mRNA levels of both GnRH-R1SHS and a previously identified receptor, GnRH-R2PEY, are highly correlated with mRNA levels of all three GnRH ligands. Despite its likely role in reproduction, we found that GnRH-R1SHS has the highest affinity for GnRH2 i
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Expression, structure, function, and evolution of gonadotropin-releasing hormone (GnRH) receptors GnRH-R1SHS and GnRH-R2PEY in the teleost, Astatotilapia burtoni.
Endocrinology, 2007Co-Authors: Colleen A. Flanagan, Russell D. Fernald, Chun-chun Chen, Marla Coetsee, Sipho Mamputha, Kathleen E. Whitlock, Nicholas Bredenkamp, Logan Grosenick, Nicola IllingAbstract:Multiple GnRH receptors are known to exist in nonmammalian species, but it is uncertain which receptor type regulates reproduction via the hypothalamic-pituitary-gonadal axis. The teleost fish, Astatotilapia burtoni, is useful for identifying the GnRH receptor responsible for reproduction, because only territorial males reproduce. We have cloned a second GnRH receptor in A. burtoni, GnRH-R1SHS (SHS is a peptide motif in extracellular loop 3), which is up-regulated in pituitaries of territorial males. We have shown that GnRH-R1SHS is expressed in many tissues and specifically colocalizes with LH in the pituitary. In A. burtoni brain, mRNA levels of both GnRH-R1SHS and a previously identified receptor, GnRH-R2PEY, are highly correlated with mRNA levels of all three GnRH ligands. Despite its likely role in reproduction, we found that GnRH-R1SHS has the highest affinity for GnRH2 in vitro and low responsivity to GnRH1. Our phylogenetic analysis shows that GnRH-R1SHS is less closely related to mammalian reprod...
