Molecular Cloning and Characterization of an Estrogen-Dependent Porcine Oviductal Secretory Glycoprotein1

Abstract

A family of estrogen-dependent porcine oviductal secretory glycoproteins (POSPs) that exhibit structural similarities are synthesized and secreted into the oviductal lumen at proestrus, estrus, and metestrus. The objectives of this study were to clone the POSP cDNA, obtain the full-length cDNA and protein sequence, examine tissue specificity and species distribution, characterize its regulation, and establish its identity by comparison to other known protein, RNA, or DNA sequences. A full-length cDNA of 2022 base pairs was obtained with an open reading frame of 1581 nucleotides, coding for a deduced protein of 527 amino acids (57 970 M(r)). The deduced protein contained three potential N-glycosylation sites, a consensus heparin-binding site, and potential O-glycosylation sites. Amino acid analysis of POSP-E3 confirmed the presence of a 21-amino acid signal sequence. Northern blot analysis revealed an oviduct-specific mRNA species of 2.25 kb in the infundibulum (INF), ampulla (A), and isthmus (I). An mRNA of similar size was detected in the oviduct of the sheep, cow, and rabbit, and one of slightly greater size (2.8 kb) in the mouse and hamster oviduct but not in the horse or alligator oviduct. Dot blot analysis indicated that steady-state levels of POSP mRNA were significantly greater (p = 0.0001) in the A than in the INF or I regardless of day of the estrous cycle and were greater on Day 0 (estrus; p = 0.0001) regardless of location. Further, steady-state mRNA levels were significantly increased (p = 0.02) on Days 0 and 1, declining rapidly to Day 2 through Day 15 of the estrous cycle. Steady-state POSP mRNA levels were significantly greater (p < 0.003) in ovariectomized gilts treated with estradiol valerate than those treated with other steroid regimens, vehicle, or no treatment (Control), consistent with estrogen control of mRNA expression. The POSP protein exhibited significant identity to oviductal glycoproteins from the baboon, cow, hamster, human, mouse, and sheep, to several mammalian nonoviductal glycoproteins; and to several chitinases. POSP joins a growing subfamily of the chitinase gene family that lacks chitinase enzymatic activity.

Regulation of IGF-I and porcine oviductal secretory protein (pOSP) secretion into the pig oviduct in the peri-ovulatory period, and effects of previous nutrition

“…In particular, the inverse relationship between protein concentrations and the concentrations of P 4 is consistent with the findings of Buhi et al [8] who showed that porcine oviductal tissue during estrus has the highest levels of de novo protein synthesis and secretion. The temporal changes in pOSP mRNA expression and the secreted pOSP proteins in relation to the time of ovulation are consistent with evidence that pOSP expression is E 2 -dependent [11]. Thus, as the steroid milieu of the oviduct became progesterone dominated by day 2 after ovulation, a major decline in both pOSP mRNA expression and pOSPs in oviduct fluid was observed.…”

“…Although previous studies have characterized IGF-I concentrations [29] and pOSP protein and mRNA abundance [11] during the estrous cycle, neither reported changes during the critical periovulatory period. Furthermore, because we have shown that the interval between the onset of estrus and the time of ovulation is highly variable in gilts, we believed it was critical to use the moment of ovulation as a critical reference point in these studies.…”

“…Blots were then hybridized overnight in fresh prehybridization solution using a 0.8 kb cDNA for pOSP, to assess steady state mRNA levels. The message detected by the probe is for pOSP 1, 2, and 3 since they are products of the same gene [11]. The cDNA fragment was labeled with [P 32 ]-dATP (Amersham Pharmacia Biotech, Baie d'Urfé, Canada) using a Random Primed DNA labeling kit according to the manufacturer's instructions (Life Technologies, Gaithersburg, MD).…”

Oviduct-specific glycoprotein and heparin modulate sperm–zona pellucida interaction during fertilization and contribute to the control of polyspermy

“…cycle, (ii) nucleotide and amino acid sequences of OGP are highly conserved between species (29) (Table S3), which agrees with the crossed action of porcine and bovine fluids, and (iii) OGP possesses heparin-binding consensus sequences (29) and heparin-binding sites (30), which would explain why heparin in the incubation medium stabilizes the hardening effect. To demonstrate the involvement of OGP in ZP modifications and its detachment in a medium lacking heparin, different experiments were performed.…”

Antibodies against the C-terminal peptide of rabbit oviductin inhibit mouse early embryo development to pass 2-cell stage

“…So it is necessary to study the function of CTP rabbit oviductin in the development of early embryo. The homology comparisons also showed that there were 40-50% smilarities between rabbit oviductin and some enzymes of chitinase gene family, but the oviductins showed no chitinase activity [14]. In recent years, few researches concerning the roles of oviductins in the development of early embryo were reported [15], [16].…”