Regulation of oxytocin receptor gene expression in sheep: tissue specificity, multiple transcripts and mRNA editing

Reproduction ◽  
2000 ◽  
pp. 187-200 ◽  
Author(s):  
HC Feng ◽  
M Bhave ◽  
RJ Fairclough

The increase in uterine oxytocin receptor concentrations over the late luteal phase of the oestrous cycle in sheep is thought to play an important role in the regulation of the duration of the cycle by facilitating the effect of oxytocin on uterine prostaglandin release. Experiments indicated that oxytocin receptor mRNA expression in the endometrium was high at oestrus compared with at days 2, 7 and 12 of the oestrous cycle. The amount of oxytocin receptor mRNA expression in the pituitary gland did not show any significant differences during the oestrous cycle. Oxytocin receptor cDNA was obtained and characterized from ovine uterine endometrium on day 15 of the oestrous cycle, using RT-PCR techniques, to study the mechanisms underlying the resolution of oxytocin receptor expression. The cDNA sequence for the oxytocin receptor gene in sheep was found to be similar to that described previously, except for a difference of seven nucleotides. These nucleotide differences resulted in changes in four of the deduced amino acids in the oxytocin receptor sequence. The heterogeneity of the different sized oxytocin receptor transcripts in sheep is due, at least in part, to the alternative use of polyadenylation sites. Northern hybridization confirmed that the oxytocin receptor gene is expressed in ovine corpus luteum. The investigations on oxytocin receptor gene expression indicate that the patten of oxytocin receptor gene expression in sheep is not only tissue-specific, but also highly function-related. Evidence was obtained of mRNA editing in both the coding and the 3'-untranslated (3'UTR) regions of oxytocin receptor gene transcripts in ovine endometrium; this was the first demonstration of this phenomenon for oxytocin receptor mRNA. The present results indicate that the observed differences in oxytocin receptor mRNA sequences for the different oxytocin receptor populations in endometrium are due to mRNA editing. mRNA editing of oxytocin receptor transcripts may be reflected in changes in the amino acid composition of the carboxyl terminus of the receptor, which would explain the differences in the observed responses to an oxytocin challenge.

1994 ◽  
Vol 344 (1309) ◽  
pp. 291-304 ◽  

The oxytocin receptor, a seven transmembrane domain, G protein-linked receptor molecule, plays a central role in determining the endocrine function of the ruminant uterine endometrium. During non- pregnant cycles the control of this molecule by circulating steroid hormones leads to regression of the corpora lutea. The kinetics of the mechanisms involved determine the time at which luteolysis occurs, and therefore the length of the oestrous cycle. In pregnancy, secretions of the trophoblast block endometrial oxytocin receptor gene expression and lead to luteal maintenance. An understanding of the molecular mechanisms involved in the steroidal control of oxytocin receptor gene expression will provide an explanation for the relative constancy of oestrous cycle lengths in non-pregnant animals. Unravelling the way in which trophoblast products block expression of the oxytocin receptor gene will lead to a better understanding of the reasons for the high rate of embryonic loss in domestic ruminants.


2015 ◽  
Vol 3 (1) ◽  
pp. e979681 ◽  
Author(s):  
E Nicole Dover ◽  
David E Mankin ◽  
Howard C Cromwell ◽  
Vipaporn Phuntumart ◽  
Lee A Meserve

1994 ◽  
Vol 12 (1) ◽  
pp. 93-105 ◽  
Author(s):  
K R Stevenson ◽  
P R Riley ◽  
H J Stewart ◽  
A P F Flint ◽  
D C Wathes

ABSTRACT A synthetic 45-mer oligonucleotide corresponding to part of the ovine endometrial oxytocin receptor cDNA was hybridized to sections of ovine uterus collected from 40 ewes at different stages during the oestrous cycle, the first 3 weeks of pregnancy and seasonal anoestrus. The quantity of oxytocin receptor mRNA was measured as the optical density (OD) value on autoradiographs using image analysis. Message first appeared in the luminal epithelium on days 14–15 of the cycle, increasing to a peak OD of 0·48 at oestrus and decreasing again between days 2 and 5. Oxytocin receptor mRNA in the superficial glands, deep glands and caruncular stroma increased between day 15 and oestrus to peak OD values of 0·17, 0·11 and 0·11 respectively, declining again by day 2 and reaching basal values (OD<0·015) by day 5. Hybridization to the myometrium tended to rise from a mean OD value of 0·01 on days 2–15 to a peak of 0·03±0·01 (mean±s.e.m.) on days 0–1, but the change was not significant. In pregnant ewes there was no detectable oxytocin receptor mRNA on days 14–15 in any region, but hybridization to the luminal epithelium was present in two of three ewes on day 21. In anoestrous ewes oxytocin receptor mRNA concentrations in all areas of the endometrium were approximately half those measured at oestrus. Optical density readings for oxytocin receptor mRNA in the various uterine compartments were compared with measurements of oxytocin receptors in the same regions as assessed by binding studies using the 125I-labelled oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH29]-vasotocin (125I-labelled OTA). In the endometrium, receptor mRNA and 125I-labelled OTA binding patterns changed in parallel, and both sets of measurements were significantly correlated (P<0·01). In the myometrium, a significant increase in 125I-labelled OTA binding occurred at oestrus; this was not accompanied by a similar increase in oxytocin receptor mRNA hybridization. This study helps to confirm that the previously identified cDNA clone is derived from the ovine oxytocin receptor, as patterns of oxytocin receptor mRNA expression in the endometrium closely resembled those of oxytocin binding. Maximum expression and binding both occurred at oestrus, suggesting that regulation of the oxytocin receptor gene in the uterus occurs principally at the transcriptional, rather than at the translational, level. Failure to detect a significant increase in myometrial mRNA expression at oestrus may indicate that the endometrial and myometrial oxytocin receptors are of different isoforms.


1995 ◽  
Vol 53 (3) ◽  
pp. 553-560 ◽  
Author(s):  
Richard Ivell ◽  
Werner Rust ◽  
Almuth Einspanier ◽  
Stefan Hartung ◽  
Michael Fields ◽  
...  

1995 ◽  
Vol 5 (8) ◽  
pp. 1585-1590
Author(s):  
T Nakamura ◽  
I Ebihara ◽  
M Fukui ◽  
S Osada ◽  
Y Tomino ◽  
...  

This study assessed glomerular endothelin (ET)-1, ET-3, and ET-receptor A and B mRNA levels in puromycin aminonucleoside (PAN)-induced nephrosis. During the nephrotic stage, 8 days after PAN injection, ET-1 and ETB receptor mRNA were elevated by 2.8 +/- 0.8-fold (P < 0.01) and 2.4 +/- 0.9-fold (P < 0.01), respectively, as compared with controls. These mRNA levels decreased to control levels by Day 20, when the nephrosis was in remission. In contrast, glomerular ETA receptor mRNA levels did not change in PAN nephrosis or control rats during the experimental period. ET-3 mRNA was not detected in the glomeruli of PAN nephrosis or control rats. Additionally, plasma ET concentration and glomerular ET production were measured in PAN nephrosis and control rats by radio-immunoassay. Eight days after PAN injection, ET-1 levels in plasma and glomeruli were not significantly altered in rats with PAN-induced nephrosis (glomeruli, 104.68 +/- 16.46 pg/mg of protein versus 98.24 +/- 13.68 pg/mg of protein; plasma, 2.68 +/- 1.10 versus 2.52 +/- 0.98 pg/mL). The administration of methylprednisolone to PAN rats resulted in the rapid disappearance of proteinuria and partially attenuated the increased ET-1 and ETB receptor gene expression in the glomeruli. These data indicate that glomerular ET-1 and ETB receptor expression in PAN nephrosis in increased at the mRNA level and that methylprednisolone treatment results in an attenuated increase.


1990 ◽  
Vol 111 (5) ◽  
pp. 2149-2158 ◽  
Author(s):  
M W Majesky ◽  
M A Reidy ◽  
D F Bowen-Pope ◽  
C E Hart ◽  
J N Wilcox ◽  
...  

Smooth muscle cells (SMC) in rat carotid artery leave the quiescent state and proliferate after balloon catheter injury, but the signals for mitogenesis are not known. In this study, the possibility that cells within damaged arteries produce a growth factor that could act locally to stimulate SMC replication and repair was examined. We found that the genes for PDGF-A and -B (ligand) and PDGF receptor (alpha and beta subunits) were expressed in normal and injured carotid arteries and were independently regulated during repair of carotid injury. Two phases of PDGF ligand and receptor gene expression were observed: (a) In the early stage, a large decrease in PDGF beta-receptor mRNA levels preceded 10- to 12-fold increases in PDGF-A transcript abundance in the first 6 h after wounding. No change in PDGF alpha-receptor or PDGF-B gene expression was found at these times. (b) In the chronic phase, 2 wk after injury, neointimal tissue had lower levels of PDGF alpha-receptor mRNA (threefold) and higher levels of PDGF beta-receptor mRNA (three- to fivefold) than did restored media. Moreover, in situ hybridization studies identified a subpopulation of neointimal SMC localized at or near the luminal surface with a different pattern of gene expression than the underlying carotid SMC. Luminal SMC were strongly positive for PDGF-A and PDGF beta-receptor transcripts, while showing little or no hybridization for PDGF-B or PDGF alpha-receptor. Immunohistochemical studies showed strongly positive staining for PDGF-A in SMC along the luminal surface. These data show that changes in PDGF ligand and receptor expression occur at specific times and locations in injured carotid artery and suggest that these changes may play a role in regulating arterial wound repair.


Endocrinology ◽  
1995 ◽  
Vol 136 (4) ◽  
pp. 1801-1804 ◽  
Author(s):  
N L Ostrowski ◽  
W S Young ◽  
S J Lolait

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