Dataset Information

Persistence of duplicated PAC1 receptors in the teleost, Sparus auratus.

ABSTRACT: : Duplicated genes are common in vertebrate genomes. Their persistence is assumed to be either a consequence of gain of novel function (neofunctionalisation) or partitioning of the function of the ancestral molecule (sub-functionalisation). Surprisingly few studies have evaluated the extent of such modifications despite the numerous duplicated receptor and ligand genes identified in vertebrate genomes to date. In order to study the importance of function in the maintenance of duplicated genes, sea bream (Sparus auratus) PAC1 receptors, sequence homologues of the mammalian receptor specific for PACAP (Pituitary Adenylate Cyclase-Activating Polypeptide), were studied. These receptors belong to family 2 GPCRs and most of their members are duplicated in teleosts although the reason why both persist in the genome is unknown.: Duplicate sea bream PACAP receptor genes (sbPAC1A and sbPAC1B), members of family 2 GPCRs, were isolated and share 77% amino acid sequence identity. RT-PCR with specific primers for each gene revealed that they have a differential tissue distribution which overlaps with the distribution of the single mammalian receptor. Furthermore, in common with mammals, the teleost genes undergo alternative splicing and a PAC1Ahop1 isoform has been characterised. Duplicated orthologous receptors have also been identified in other teleost genomes and their distribution profile suggests that function may be species specific. Functional analysis of the paralogue sbPAC1s in Cos7 cells revealed that they are strongly stimulated in the presence of mammalian PACAP27 and PACAP38 and far less with VIP (Vasoactive Intestinal Peptide). The sbPAC1 receptors are equally stimulated (LOGEC50 values for maximal cAMP production) in the presence of PACAP27 (-8.74 +/- 0.29 M and -9.15 +/- 0.21 M, respectively for sbPAC1A and sbPAC1B, P > 0.05) and PACAP38 (-8.54 +/- 0.18 M and -8.92 +/- 0.24 M, respectively for sbPAC1A and sbPAC1B, P > 0.05). Human VIP was found to stimulate sbPAC1A (-7.23 +/- 0.20 M) more strongly than sbPAC1B (-6.57 +/- 0.14 M, P < 0.05) and human secretin (SCT), which has not so far been identified in fish genomes, caused negligible stimulation of both receptors.: The existence of functionally divergent duplicate sbPAC1 receptors is in line with previously proposed theories about the origin and maintenance of duplicated genes. Sea bream PAC1 duplicate receptors resemble the typical mammalian PAC1, and PACAP peptides were found to be more effective than VIP in stimulating cAMP production, although sbPAC1A was more responsive for VIP than sbPAC1B. These results together with the highly divergent pattern of tissue distribution suggest that a process involving neofunctionalisation occurred after receptor duplication within the fish lineage and probably accounts for their persistence in the genome. The characterisation of further duplicated receptors and their ligands should provide insights into the evolution and function of novel protein-protein interactions associated with the vertebrate radiation.

SUBMITTER: Cardoso JC

PROVIDER: S-EPMC2245808 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Persistence of duplicated PAC1 receptors in the teleost, Sparus auratus.

Cardoso João C R JC de Vet Edwin C J M EC Louro Bruno B Elgar Greg G Clark Melody S MS Power Deborah M DM

BMC evolutionary biology 20071112

<h4>Background</h4>: Duplicated genes are common in vertebrate genomes. Their persistence is assumed to be either a consequence of gain of novel function (neofunctionalisation) or partitioning of the function of the ancestral molecule (sub-functionalisation). Surprisingly few studies have evaluated the extent of such modifications despite the numerous duplicated receptor and ligand genes identified in vertebrate genomes to date. In order to study the importance of function in the maintenance of ...[more]

PMID: 17997850

Similar Datasets

Project description:BACKGROUND: Fish scales are an important reservoir of calcium and phosphorus and together with the skin function as an integrated barrier against environmental changes and external aggressors. Histological studies have revealed that the skin and scales regenerate rapidly in fish when they are lost or damaged. In the present manuscript the histological and molecular changes underlying skin and scale regeneration in fed and fasted sea bream (Sparus auratus) were studied using a microarray 3 and 7 days after scale removal to provide a comprehensive molecular understanding of the early stages of these processes. RESULTS: Histological analysis of skin/scales revealed 3 days after scale removal re-epithelisation and formation of the scale pocket had occurred and 53 and 109 genes showed significant up or down-regulation, respectively. Genes significantly up-regulated were involved in cell cycle regulation, cell proliferation and adhesion, immune response and antioxidant activities. 7 days after scale removal a thin regenerated scale was visible and only minor changes in gene expression occurred. In animals that were fasted to deplete mineral availability the expression profiles centred on maintaining energy homeostasis. The utilisation of fasting as a treatment emphasised the competing whole animal physiological requirements with regard to barrier repair, infection control and energy homeostasis. CONCLUSIONS: The identification of numerous genes involved in the mitotic checkpoint and cell proliferation indicate that the experimental procedure may be useful for understanding cell proliferation and control in vertebrates within the context of the whole animal physiology. In response to skin damage genes of immune surveillance were up-regulated along with others involved in tissue regeneration required to rapidly re-establish barrier function. Additionally, candidate fish genes were identified that may be involved in cytoskeletal re-modelling, mineralization and stem cells, which are of potential use in aquaculture and fish husbandry, as they may impact on the ability of the fish to produce structural proteins, such as muscle, efficiently.

Project description:The mediation of fluid homeostasis by multiple classes of aquaporins has been suggested to be essential during spermatogenesis and spermiation. In the marine teleost gilthead seabream (Sparus aurata), seven distinct aquaporins, Aqp0a, -1aa, -1ab, -7, -8b, -9b and -10b, are differentially expressed in the somatic and germ cell lineages of the spermiating testis, but the endocrine regulation of these channels during germ cell development is unknown. In this study, we investigated the in vivo developmental expression of aquaporins in the seabream testis together with plasma androgen concentrations. We then examined the in vitro regulatory effects of recombinant piscine gonadotropins, follicle-stimulating (rFsh) and luteinizing (rLh) hormones, and sex steroids on aquaporin mRNA levels during the spermatogenic cycle. During the resting phase, when plasma levels of androgens were low, the testis exclusively contained proliferating spermatogonia expressing Aqp1ab, whereas Aqp10b and -9b were localized in Sertoli and Leydig cells, respectively. At the onset of spermatogenesis and during spermiation, the increase of androgen plasma levels correlated with the additional appearance of Aqp0a and -7 in Sertoli cells, Aqp0a in spermatogonia and spermatocytes, Aqp1ab, -7 and -10b from spermatogonia to spermatozoa, and Aqp1aa and -8b in spermatids and spermatozoa. Short-term in vitro incubation of testis explants indicated that most aquaporins in Sertoli cells and early germ cells were upregulated by rFsh and/or rLh through androgen-dependent pathways, although Aqp1ab in proliferating spermatogonia was also activated by estrogens. However, expression of Aqp9b in Leydig cells, and of Aqp1aa and -7 in spermatocytes and spermatids, was also directly stimulated by rLh. These results reveal a complex gonadotropic control of aquaporin expression during seabream germ cell development, apparently involving both androgen-dependent and independent pathways, which may assure the fine tuning of aquaporin-mediated fluid secretion and absorption mechanisms in the seabream testis.

Dataset Information

Persistence of duplicated PAC1 receptors in the teleost, Sparus auratus.

Publications

Persistence of duplicated PAC1 receptors in the teleost, Sparus auratus.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets