Mammalian Mesotocin: cDNA Sequence and Expression of an Oxytocin-like Gene in a Macropodid Marsupial, the Tammar Wallaby

Parry, Laura J.; Bathgate, Ross A. D.; Ivell, Richard

doi:10.1006/gcen.2000.7464

Cited by 8 publications

(3 citation statements)

References 39 publications

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“…Early work found no MT or OT protein in extracts of corpora lutea from pregnant tammar wallabies (Curlewis et al 1988). However, evidence of an MT gene transcript has been shown in the preovulatory follicle and corpus luteum (Parry et al 2000). These studies confirm that the tammar ovary has the ability to synthesise MT and suggest that an ovarian OT physiology was present early in the evolution of mammals.…”

Section: Uterine and Ovarian Mesotocin Receptor Expression 645supporting

confidence: 70%

Differential expression of mesotocin receptors in the uterus and ovary of the pregnant tammar wallaby

Siebel¹,

Bathgate²,

Parry³

2005

Reproduction

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Mesotocin, an oxytocin-like peptide, is released in highest concentrations during parturition in macropodid marsupials. In late pregnant wallabies, uterine sensitivity to mesotocin increases markedly in the myometrium of the gravid uterus. This coincides with a significant increase in myometrial mesotocin receptor concentrations 3-4 days before term. To date, there is no information on mesotocin receptor gene expression in female wallaby reproductive tissues. This study aimed to examine mesotocin receptor gene expression in the uterus and ovaries of pregnant tammar wallabies, and to localise mesotocin receptors within the uterus. An RT-PCR strategy produced a consensus nucleotide sequence of 834 bp, which encoded 278 amino acids of transmembrane domains I to VI. This protein sequence has approximately 80% homology with the bovine and rat oxytocin receptor exon 2 region. Only one mesotocin receptor was detected in the tammar genome. The myometrium and mammary gland both expressed a 4.1 kb mesotocin receptor gene transcript. Myometrial mesotocin receptor gene expression increased on day 22 of the 26-day gestation and was significantly higher in the gravid than the non-gravid uterus in late pregnancy. This pattern of mesotocin receptor gene expression paralleled mesotocin receptor concentrations. Mesotocin binding sites were localised only to the myometrium, the highest densities being observed in the gravid uterus. Finally, this study showed high expression of mesotocin receptors in the corpus luteum. The pattern of luteal mesotocin receptor expression differed from the myometrium, with a decrease in mesotocin receptors occurring on the day of expected births. (Kubota et al. 1996) and rhesus monkey (Salvatore et al. 1998). Unlike eutherians, which secrete OT, marsupials secrete mesotocin (MT), which differs from OT by one amino acid, an isoleucine for leucine at position 8. The presence of OT-like receptors in marsupials was first demonstrated in the brushtail possum uterus, mammary gland and median vaginal sacs (Sernia et al. 1990(Sernia et al. , 1991. These studies reported that the OTbinding site was not specific for MT over OT, vasotocin (AVT) or arginine vasopressin (AVP). This work was supported by data from two separate studies which demonstrated a single OT-binding site in uterine tissues of the pregnant tammar wallaby, using either 125 I-oxytocin The tammar wallaby (Macropus eugenii) is a well-established model to differentiate between the role of maternal systemic and fetal-specific factors in the regulation of uterine MT receptors during pregnancy. Female tammar wallabies give birth to small, altricial young after a short gestation period of only 26 days after reactivation of the diapausing blastocyst . They have two anatomically separate uteri, which open into the anterior vaginal expansion via separate cervices (Tyndale-Biscoe & Renfree 1987). Due to the unique reproductive tract anatomy of marsupials, the influence of the conceptus on the regulation of myometrial MT receptors can be isolat...

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Section: Uterine and Ovarian Mesotocin Receptor Expression 645supporting

confidence: 70%

Differential expression of mesotocin receptors in the uterus and ovary of the pregnant tammar wallaby

Siebel¹,

Bathgate²,

Parry³

2005

Reproduction

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“…In elasmobranchs, a host of different neutral peptide homologs has been reported which is in contrast with the remarkable stability in the type and numbers of nonapeptides in any other group of Vertebrata (Acher, 1996 ). Presence of more than two neurohypophyseal peptides has been reported from groups like elasmobranchs, amphibians, and metatherians (Chauvet et al, 1983 , 1984 , 1985 ; Rouille et al, 1988 , 1989 ; Parry et al, 2000 ; Hyodo et al, 2004 ). In teleosts, VT and IT have been reported as the basic and neutral hormone representatives, respectively.…”

Section: Introductionmentioning

confidence: 97%

Molecular cloning, sequencing and tissue expression of vasotocin and isotocin precursor genes from Ostariophysian catfishes: phylogeny and evolutionary considerations in teleosts

2015

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Basic and neutral neurohypophyseal (NH) nonapeptides have evolved from vasotocin (VT) by a gene duplication at the base of the gnathostome lineage. In teleosts, VT and IT are the basic and neutral peptides, respectively. In the present study, VT and IT precursor genes of Heteropneustes fossilis and Clarias batrachus (Siluriformes, Ostariophysi) were cloned and sequenced. The channel catfish Icatalurus punctatus NH precursor sequences were obtained from EST database. The catfish NH sequences were used along with the available Acanthopterygii and other vertebrate NH precursor sequences to draw phylogenetic inference on the evolutionary history of the teleost NH peptides. Synteny analysis of the NH gene loci in various teleost species was done to complement the phylogenetic analysis. In H. fossilis, the NH transcripts were also sequenced from the ovary. The cloned genes and the deduced precursor proteins showed conserved characteristics of the NH nonapeptide precursors. The genes are expressed in brain and ovary (follicular envelope) of H. fossilis with higher transcript abundance in the brain. The addition of the catfish sequences in the phylogenetic analysis revealed that the VT and IT precursors of the species-rich superorders of teleosts have a distinct phylogenetic history with the Acanthopterygii VT and IT precursors sharing a less evolutionary distance and the Ostariophysi VT and IT having a greater evolutionary distance. The genomic location of VT and IT precursors, and synteny analysis of the NH loci lend support to the phylogenetic inference and suggest a footprint of fish- specific whole genome duplication (3R) and subsequent diploidization in the NH loci. The VT and IT precursor genes are most likely lineage-specific paralogs resulting from differential losses of the 3R NH paralogs in the two superorders. The independent yet consistent retention of VT and IT in the two superorders might be directed by a stringent ligand-receptor selectivity.

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“…In the cartilaginous fish, a host of various neutral peptides are present in different species . Amongst tetrapods, the duality of both basic and neutral hormone precursors has been reported in Metatheria . Such instances may point to additional lineage‐specific duplications.…”

Section: Introductionmentioning

confidence: 99%

Molecular cloning and characterisation of an isotocin paralogue ([V8] isotocin) in catfishes (superorder Ostariophysi): Origin traced likely to the fish‐specific whole genome duplication

Banerjee

Chaube

Joy

2018

J Neuroendocrinology

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The present study reports the molecular cloning of a previously uncharacterised neurohypophyseal nonapeptide precursor cDNA in two catfish species: Heteropneustes fossilis and Clarias batrachus. The deduced nonapeptide is CYISNCPVG ([V8] isotocin), which has not been reported in any vertebrate till date. Phylogenetic and conserved synteny analyses showed the gene to have originated from the isotocin precursor (pro‐it) gene by fish‐specific whole genome duplication (3R). The two isotocin lineages have been designated as pro‐ita (new gene) and pro‐itb (conventional it gene). All teleost groups may not possess both pro‐ita and pro‐itb and the pattern of losses/retention was found to be lineage‐specific. Quantitative reverse transcriptase‐polymerase chain reaction studies showed the expression of the pro‐ita gene in the brain and ovary of H. fossilis. In situ hybridisation studies localised the pro‐ita transcripts in the nucleus preopticus of the hypothalamus and the follicular layer (theca‐granulosa) of oocytes, comprising tissues in which pro‐itb and vasotocin precursor (pro‐vt) mRNA expression was previously reported. The transcript levels varied with the reproductive stage and a high abundance was found in both brain and ovary during the breeding phase. The substitution of valine in place of isoleucine at the eighth position in Ita may have modified the ligand‐receptor interaction, leading to sub‐functionalisation and the retention of the gene in catfishes.

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Mammalian Mesotocin: cDNA Sequence and Expression of an Oxytocin-like Gene in a Macropodid Marsupial, the Tammar Wallaby

Cited by 8 publications

References 39 publications

Differential expression of mesotocin receptors in the uterus and ovary of the pregnant tammar wallaby

Differential expression of mesotocin receptors in the uterus and ovary of the pregnant tammar wallaby

Molecular cloning, sequencing and tissue expression of vasotocin and isotocin precursor genes from Ostariophysian catfishes: phylogeny and evolutionary considerations in teleosts

Molecular cloning and characterisation of an isotocin paralogue ([V8] isotocin) in catfishes (superorder Ostariophysi): Origin traced likely to the fish‐specific whole genome duplication

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