Placenta
Volume 31, Issue 1 , Pages 11-17, January 2010

The Glycosylation Pattern of Secretory Granules in Binucleate Trophoblast Cells is Highly Conserved in Ruminants

  • K. Klisch

      Affiliations

    • School of Veterinary Medicine & Science, University of Nottingham, Sutton Bonington Campus, College Road, Sutton Bonington, Leicestershire, LE12 5RD, UK
    • Corresponding Author InformationCorresponding author. Tel.: +44 115 95 16247.
    • ,
  • F.B.P. Wooding

      Affiliations

    • Department of Physiology, Development and Neuroscience, University of Cambridge, UK
    • ,
  • C.J.P. Jones

      Affiliations

    • Maternal and Fetal Health Research Group, University of Manchester, UK

Accepted 3 November 2009. published online 03 December 2009.

Article Outline

Abstract 

The binucleate trophoblast cells (BNCs) in the ruminant placenta are a unique feature of this taxon. These cells produce several secretory proteins and transfer these across the fetomaternal barrier into the dam. We used lectin histochemistry with a panel of 24 lectins to characterise the glycosylation pattern of BNC secretory granules in a variety of ruminants. Seven species out of three ruminant families were thus investigated: greater malayan chevrotain (Tragulidae); fallow deer, red deer, chinese water deer (Cervidae); and domestic goat, springbok, impala (Bovidae).

BNC granules in all species studied strongly expressed tri-/tetraantennary complex N-glycans and bisecting N-acetylglucosamine [GlcNAc] as shown by binding of leuco- and erythroagglutins of Phaseolus vulgaris respectively. The presence of terminal N-acetylgalactosamine [GalNAc]) in BNC granules is shown by intense staining with lectins from Dolichos biflorus, Vicia villosa and Wisteria floribunda. Terminal galactose or GalNAc was also present, bound by Glycine max agglutinin. Treatment of slides with neuraminidase strongly intensified staining of Erythrina cristagalli lectin (ECA) to terminal lactosamine in all species studied; this was otherwise absent except in goat. Sambucus nigra-1 lectin bound to BNC granules in all species except in Impala, indicating the presence of abundant alpha2,6 linked sialic acid.

These results indicate that these unusual highly branched glycans, with bisecting GlcNAc and terminal GalNAc are a general feature of BNC granules in Ruminants, including the most basal Tragulid branch. It therefore appears that the specific glycosylation pattern of BNC granules evolved early in ruminant phylogenesis, together with the appearance of BNC. The conserved glycan structure in BNC secretory granules indicates that this pattern of glycosylation is likely to be of considerable functional importance for the secretory glycoproteins of ruminant BNC.

Keywords: Evolution, Artiodactyla, Lectin

 

Back to Article Outline

1. Introduction 

Compared to most other organs, the placenta is unique in its wide variation of macroscopical and microscopical structure [1]. This attracted the curiosity of many researchers over the last centuries, but plausible explanations for this phenomenon have been provided only in the last decade [2], [3], [4]. The consolidation of the mammalian phylogenetic tree with molecular data [5], [6] made it possible to track down the transitions of placental features in the evolution of cetartiodactyls, which contain artiodactyls, cetaceans and hippos [7].

Most ruminant placentae are cotyledonary structures in which an intense interdigitation of fetal and maternal tissue is restricted to specific localisations called placentomes. Only in the most basal ruminant branch, the Tragulidae (mouse deer, chevrotains) are these placentomes absent and interdigitation is diffusely spread over the entire chorionic surface [8]. The one feature which is characteristic for ALL ruminants is the presence of binucleate trophoblast cells (BNC). These cells are believed to develop in the trophoblast from uninucleate trophoblast cells by acytokinetic mitosis [9]. The BNC fuse with cells of the uterine epithelium or with syncytia, which were already formed by previous fusions. This formation of syncytia of mixed fetal and maternal origin leads to the classification of the ruminant placenta as synepitheliochorial [9]. One well documented function of this fusion process is the delivery of trophoblast derived proteins, which are stored in BNC granules, from the trophoblast into the fetomaternal syncytial part of the placenta [10], [11], [12]. These granules are then exocytosed at the syncytial basal membrane and may act either locally or systemically in the dam.

Several lectin histochemical studies [13], [14], [15], [16], [17] showed that BNC granules in ruminants have a specific glycosylation pattern, which differs from that of uninucleate trophoblast cells. In the present study we use a panel of lectins to characterise the glycosylation pattern of BNC granules in a variety of ruminant species. This approach makes it possible to identify phylogenetically conserved patterns of glycosylation.

Back to Article Outline

2. Methods 

Placental tissue was obtained from the Greater malayan chevrotain (Tragulus napu), Red Deer (Cervus elaphus), Fallow Deer (Dama dama), Chinese Water Deer (Hydropotes inermis), Goat (Capra hircus), Springbok (Antidorcas marsupialis), and Impala (Aepyceros melampus). The tissue was fixed (3% formaldehyde in PBS, plus 1% glutaraldehyde/5% sucrose for some specimens) and embedded in epoxy resin. Sections (0.75 μm thick) were cut for lectin histochemistry, mounted on 3′-aminopropyltriethoxysilane-coated slides [18] and stained with a panel of 24 biotinylated lectins (for major specificity of these lectins see Table 1) and an avidin–peroxidase revealing system as previously described by [19]. Resin was removed with saturated sodium ethoxide, diluted 1:1 with absolute ethanol, for 15 min and, after washing in ethanol followed by distilled water, endogenous peroxidase was blocked with 10% (v/v) hydrogen peroxide (100 volumes, BDH, Poole, UK) before exposure to 0.03% (w/v) trypsin (Type II-S, Sigma) in 0.05 M Tris buffered saline (TBS), pH 7.6, for 4 min at 37 °C. After washing, sections were incubated with 10 μg/ml biotinylated lectin (Sigma; SNA-1 from Boehringer Mannheim, Lewes, UK; ALA, MAA, DSA and STA from Vector Laboratories, Peterborough, UK; AAA from EY Laboratories, San Mateo, CA, USA; see Table 1 for explanation of lectin abbreviations) in 0.05 M TBS containing 1 mM calcium chloride for 1 h at 37 °C. After washing in the same buffer, they were incubated with 5 μg/ml avidin–peroxidase (Sigma) in 0.125 M TBS, pH 7.6, containing 0.347 M sodium chloride for 1 h at 37 °C. Sections were washed and sites of lectin binding were revealed with 0.05% (w/v) diaminobenzidine tetrahydrochloride dihydrate (Aldrich Chemical Co., Gillingham, UK) in 0.05 M TBS, pH 7.6, and 0.015% (v/v) hydrogen peroxide (100 volumes) for 5 min at 18°C ± 0.5 °C. Sections were rinsed, air-dried and mounted in neutral synthetic mounting medium (BDH).

Table 1. Specificities of the lectins used in this study.
AcronymSourceMajor specificityReference
AAAAnguilla anguilla
Eel		H type 1 antigen, LeaBaldus et al. [20]
AHAArachis hypogaea
Peanut		Galβ1,3GalNAcβ1->Galβ1,4GlcNAcβ1-Lotan and Sharon [21]
Sueyoshi et al. [22]
ALAAleuria aurantia
Mushroom		Fucose linked α1,6- to GlcNAcDebray and Montreuil [23]
BSA-1B4Bandeiraea simplicifolia
Griffonia		Galα1,3Gal-; Galα1,4Ga-lWu et al. [24]
DBADolichos biflorus
Horse Gram		GalNAcα1,3(Fucα1,2)Gal-β1,3/4GlcNAcβ1-GalNAcß1,4[NeuAcα2,3}Gal-Piller et al. [25]
Wu et al. [26]
DSADatura stramonium
Jimson Weed		β1,4GlcNAc, N-Acetyllactosamine > chitotrioseCrowley et al. [27]
Yamashita et al. [28]
ECAErythrina cristagalli
Coral Tree		Galβ1,4GlcNAcβ1-De Boeck et al. [29]
GNAGalanthus nivalis
Snowdrop		Nonreducing terminal a-d-mannose, especially the mannosyl α1,3mannose linkageShibuya et al. [30]
HPAHelix pomatia
Roman snail		Terminal GalNAcα1-Iskratsch et al. [31]
LEALycopersicon esculentum
Tomato		β1,4GlcNAc oligomersNachbar et al. [32]
LTATetragonolobus purpureus
Lotus		L-fucosyl terminals (especially where clustered), Fucα1,6GlcNAc >Fucα1,2-Galß1,4(Fucα1,3)-GlcNAcß, Lex, yPereira and Kabat [33]
Debray et al. [34]
Yan et al. [35]
MAAMaackia amurensisNeuNAcα2,3 Galβ1-Wang and Cummings [36]
MPAMaclura pomifera
Osage orange		Galβ1,3GalNAcα1->GalNAcα1-Sarkar et al. [37]
PAAPhytolacca americana
Pokeweed		Poly-N-acetyllactosamine, GlcNAc oligomersIrimura and Nicolson [38]
Yamaguchi et al. [39]
PHA-EPhaseolus vulgaris
(erythroagglutinin)
Kidney Bean		Bisected complex N-linked sequencesKaneda et al. [40]
PHA-LP. vulgaris (leukoagglutinin)
Kidney Bean		β1-6 linked GlcNAc in tri/tetra-antennary complex N-linked sequencesKaneda et al. [40]
PSAPisum sativum
Garden Pea		α-d-mannose in non-bisected bi/tri-antennary, complex N-linked sequencesDebray et al. [34]
SBAGlycine max
Soybean		Terminal GalNAcα1- >Galα1Bhattacharyya et al. [41]
SNA-1Sambucus nigra
Elderberry Bark		NeuNAcα2,6Gal-Iskratsch et al. [31]
STASolanum tuberosum
Potato		β1,4GlcNAc oligomersDebray et al. [34]
UEA-1Ulex europaeus-1
Gorse		H type 2 antigen (αL-Fuc(1,2)- Galβ1,4GlcNAcβ1-) and LeyBaldus et al. [20]
VVAVicia villosa
Hairy vetch		Terminal GalNAc α/β1-Iskratsch et al. [31]
Wu et al. [26]
WFAWisteria floribunda
Wisteria		Terminal GalNAc α/β1-Piller et al. [25]
WGATriticum vulgaris
Wheatgerm		NeuNAcα2,3 Gal- or HexNAcβ1,4-Iskratsch et al. [31]

Negative controls were carried out by substitution of 0.05 M TBS containing 1 mM calcium chloride, pH 7.6, for the lectin, in order to identify non-specific binding of avidin–peroxidase to the tissue or residual endogenous peroxidase activity. Sections were also incubated with lectin in the presence of the appropriate competing sugar: 0.2 Mα-methyl mannoside for GNA and PSA, 0.2 M l-fucose for LTA, UEA-1, AAA and ALA, 0.2 M galactose for AHA, ECA, MPA and WFA, 0.2 M N-acetylgalactosamine for SBA, DBA, VVA, BSA-1B4 and HPA, 0.05 M N-acetyllactosamine for DSA, 0.2 M N-acetylglucosamine for STA and LEA and 0.05 M tri-N-acetylchitotriose for PAA and WGA. No simple sugars are available to compete for the binding of PHA-E and PHA-L, and neuraminidase pre-treatment (0.1 units/ml, Type VI from Clostridium perfringens (Sigma) for 2 h at 37 °C) [42] was used to control the sialic acid-binding lectins. Sections stained with AHA, ECA, SBA, PAA and WGA were also exposed to neuraminidase before incubation in the lectin to cleave off terminal sialic acid.

The slides were evaluated with a LEICA DM5000B microscope and the staining intensities of BNC granules were recorded using a semiquantitative grading scale (no staining = 0, maximal staining = 4).

Back to Article Outline

3. Results 

The use of semithin sections allowed a good spatial resolution of the sections and the recognition of BNC, despite some differences in fixation and preservation. Individual granules in the BNC could be visualised in many sections (see Fig. 1C, F and Fig. 2B, D), but some lectins resulted in an intense staining of all the BNC cytoplasm (Figs. 1A, 2A), which obscured the individual granules. The staining intensities for the 24 lectins are summarised in Table 2. Additional data for cattle (Bos taurus) and sheep (Ovis aries) were added to the table from a previous publication [15].

  • View full-size image.
  • Fig. 1 

    The fetal (F) and maternal (M) stroma is labelled in all micrographs to facilitate the identification of the respective placental compartments. A Tragulus, DBA staining. Two chorionic villi (fetal stroma marked with F) are separated by a maternal septum (M). Three BNC (arrows) with strongly stained granules are located in the trophoblast epithelium. One BNC (arrowhead) is now part of a fetomaternal syncytial plaque and is in contact with the maternal stroma. (Magnification bar = 20 μm for all figures). B Red Deer, DBA staining. The fetomaternal contact line is marked by arrowheads. BNC with stained granules can be seen in the trophoblast epithelium (above the fetomaternal contact line) and as part of fetomaternal trinucleate cells in the uterine epithelium (below that line). C Goat, WFA staining. BNC with intensely stained granules are marked by arrows. Since there is more staining of other structures (mainly maternal stroma) the cells are less conspicuous. D Goat, SBA staining. Intensively stained granules can be seen in BNC (arrows), but also basally in the uterine epithelium (arrowhead). E Red Deer VVA staining. F Goat HPA staining. Staining of BNC granules is slightly less intense than with other GalNac binding lectins.

  • View full-size image.
  • Fig. 2 

    A Tragulus PHA-L (magnification bar = 20  μm for all figures). BNC show an intense staining of the cytoplasm, while the nuclei remain unstained. B Water Deer PHA-E staining, showing moderate binding to granules. C Fallow Deer ECA staining. The BNC are just recognisable as unstained shadows (arrowhead). D Fallow Deer ECA + Neuraminidase. Treatment with neuramindase unmasks the ECA binding glycotope and results in a moderate staining of BNC granules (arrowheads). E Tragulus SNA-1 staining. BNC are clearly visible. F Impala SNA-1 staining. The BNC remain unstained, while maternal and fetal capillary endothelia show a moderate labelling.

Table 2. Results of the lectin staining. The staining intensities of BNC granules were recorded on a semiquantitative grading scale (no staining = 0, maximal staining = 4). Data from cattle and sheep were obtained from an earlier publication [15]. If no data were available for a specific lectin the field is left blank. Cases where a pre-treatment of slides with neuraminidase (N) was performed are flagged by +N.

Several lectins (PHA-E, PHA-L, ALA, DBA, WFA, VVA, SBA,) showed a moderate to strong (grade 2–4) staining of BNC granules in all species studied, while some other lectins (LTA, UEA-1, AAA, BSA-1B4) showed no significant binding to BNC granules in BNC of any species.

The presence of terminal N-acetylgalactosamine [GalNAc] was demonstrated by an intense staining with lectins from Dolichos biflorus (DBA), Vicia villosa (VVA), Wisteria floribunda (WFA) and Soy bean agglutinin from Glycine max (SBA) (Fig. 1).

BNC in all species studied (see Fig. 2A, B) strongly expressed N-glycans with bisecting N-acetylglucosamine [GlcNAc] and tri-/tetraantennary complex N-glycans shown by binding of erythro- and leucoagglutinins of Phaseolus vulgaris (PHA-E, PHA-L) respectively (see Fig. 3 for a detailed structure of this type of glycan).

  • View full-size image.
  • Fig. 3 

    Schematic drawing of the main N-glycan carried by PAGs in bovine BNC [46]. The tetraantennary glycan is attached to an asparagine (Asn) residue of the protein. Dotted circles mark the structural patterns which are important for lectin binding to this carbohydrate. The terminal α2,3-linked sialic acid (NeuAc) in this structure is not recognised by MAA-lectin, probably due to steric hindrance by the GalNAc linked to the subterminal Gal [46].

Treatment of slides with neuraminidase strongly intensified staining of Erythrina cristagalli lectin (ECA) to terminal lactosamine (Galβ1,4GlcNAc-) in all species studied (Fig. 2C,D). Sambucus nigra-1 lectin (SNA-1) bound to BNC granules in all species (Fig. 2E) except Impala (Aepyceros melampus) (Fig. 2F), indicating the presence of abundant α2,6 linked sialic acid.

Back to Article Outline

4. Discussion 

The BNC are the characteristic feature of the ruminant placenta. This cell type has been found in all ruminant placentas, including the most basal phylogenetic branch, the tragulidae [8]. The cotyledonary type of placenta evolved after the branching of the tragulids and is therefore only present in the higher ruminants (pecora), being absent in tragulidae (Fig. 4) [7]. Consequently only BNC, not cotyledons, can be considered as a defining characteristic of ruminants. The BNC have a complex life history in which they fuse with cells in the maternal uterine epithelium and release granules, which contain secretory proteins, into the maternal uterine stroma [9]. Therefore the BNC can be regarded as a means to deliver proteins from the fetal compartment of the placenta into the maternal organism. Proteins which have been identified in the BNC granules are pregnancy associated glycoproteins (PAGs) [12], placental lactogen (PL) [10], and prolactin related protein-1 (PRP-1) [43]. In cattle all these proteins are glycoproteins while in sheep and goat PL is not glycosylated [44]. The present study characterises the glycosylation of such secretory proteins in BNC granules in a variety of ruminant species. Earlier lectin histochemical studies described the glycosylation of BNC in cattle [13], [14], [15], [17], sheep [15] and water buffalo [45]. All these studies demonstrate that the glycosylation of BNC granules differs significantly from that of the uninucleate trophoblast cell cytoplasm. The three species in these studies cited above belong to the bovid clade and conserved staining patterns of BNC within this group were demonstrated. In the present study we use a wider collection of more distantly related ruminants to investigate lectin staining patterns of BNC granules. This collection of specimens included sections of a tragulid, which belongs to the most basal branch of the ruminant phylogenetic tree (Fig. 4).

  • View full-size image.
  • Fig. 4 

    Phylogenetic tree of the ruminants (modified from [5]). Species used in this study are highlighted. The binucleate trophoblast cells (BNC) are present in all ruminants, while the cotyledonary placenta type is found only in the higher ruminants (pecora).

Our study shows that one feature common to all is the presence of terminal GalNAc residues, demonstrated by staining with DBA, WFA, VVA, and SBA. In cattle it has been shown that the DBA, VVA and WFA primarily bind to N-glycans which are attached to PAGs and also to PRP-1 [17]. In PAGs this terminal GalNAc is part of the Sd(a)-epitope (NeuAcα2-3 [GalNAcβ1-4]Galβ1-4GlcNAc-) on a tetraantennary N-glycan (Fig. 3)[46]. This specific glycosylation of secretory proteins in BNC has been used for the purification of PAGs by lectin affinity chromatography in cattle [47], water buffalo [48], European bison [49] and American bison [50]. The presence of terminal GalNAc in BNC granules of all studied species suggests that lectin affinity chromatography is likely to be suitable for the purification of PAGs from BNC in all ruminants. The purification of PAGs and the raising of specific antibodies against these proteins could be of practical value for the development of serological pregnancy tests in ruminants outside the bovidae. Serological pregnancy testing with antibodies against bovid PAGs works in cervids [51], but the development of species-specific antibodies might increase the test sensitivity or might even be essential for testing in more distantly related ruminants. In cattle it had been shown that the presence of terminal GalNAc residues in BNC changes during the course of pregnancy. Binding of DBA to BNC is absent on day 29, but can be detected on day 40 of pregnancy [14]. A similar change has been observed with the monoclonal antibody CT-1, which recognises the Sd(a)-glycotope in BNC [46]. Staining of BNC with DBA is detectable during most of the remaining pregnancy, but it disappears at parturition [52]. Whether such changes during pregnancy also apply to other ruminants will need further studies.

In bovine BNC the terminal GalNAc is part of the Sd(a)-epitope [46] (also see Fig. 3). Western analysis [17] and lectin affinity chromatography, followed by peptide fingerprinting by MALDI-mass spectrometry [47] showed that terminal GalNAc is associated primarily with PAGs and to a lesser extent with PRP-I. In these studies no evidence was found that PL, which like PAG and PRP-I is produced by the BNC, also carries this specific glycosylation pattern. This is in accordance with Byatt et al. [53], who partially characterised the N-glycans of bovine PL. That study shows that a triantennary sialylated structure, without any terminal GalNAc, is the predominant glycan on bovine PL. This points to the interesting fact that in the BNC different secretory glycoproteins are decorated with different N-glycans: PAGs and PRP-I, but not PL, carry terminal GalNAc glycotopes.

Terminal alpha 2-6 linked sialic acid, detected by S. nigra agglutinin (SNA-1), is found in BNC granules in most species, but is completely absent in the Impala. One earlier study [15] revealed that this glycotope is also absent in bovine BNC. Within the bovids only Cattle and Impala have been shown not to express alpha 2-6 linked sialic acid, while all other bovids investigated express it. This suggests that the loss of alpha 2-6 linked sialic acid occurred independently in the evolution of cattle and Impala. In most species the treatment with neuraminidase abolished the SNA-1 staining. Treatment of the sections with neuraminidase allowed binding of ECA, which was otherwise absent (except in Goat and Sheep). This indicates that ECA binding structures (Galβ1,4GlcNAc) were masked by sialic acid. Together with the lack of MAA staining (specific for NeuAcα2,3Galβ) in most species and the presence of SNA-staining, this suggests a widespread presence of NeuAcα2,6 Galβ1,4GlcNAc epitopes.

The two lectins from P. vulgaris (PHA-E and PHA-E) bind to BNC granules of all the species studied. These lectins recognise different branching patterns in complex N-glycans [40]. Bisecting GlcNAc is recognised by PHA-E, while β1,6 GlcNAc in tri-or tetraantennary glycans is recognised by PHA-L. Previous studies of the synthesis of N-glycans showed that the presence of a bisecting GlcNAc inhibits the initiation of a tri- and tetraantennary branching pattern by the N-acetylglucosaminyltransferases IV and V [54]. Therefore the simultaneous presence of bisecting GlcNAc in tri- and tetraantennary glycans is a most unusual feature. In cattle, the BNC are clearly able to synthesise such structures [46]. In the present study the histochemical colocalisation of PHA-E and PHA-L does not necessarily mean that there is bisecting GlcNAc on tri-or tetraantennary glycans. It could also be dispersed on separate glycans on different glycoproteins or in different subpopulations of granules within the same cell. In cattle PHA-L binds to BNC earlier than the lectins specific for GalNAc [46], and binding is still present at parturition [50]. If this constant binding to BNC is also the case in all ruminant species, PHA-L could be a suitable marker for BNC at all stages of pregnancy.

Abundant residues of terminal GalNAc, demonstrated by DBA, WFA, VVA, and SBA binding, and the branching pattern recognised by the PHA lectins is conserved in BNC of all studied ruminants, including the mouse deer. This indicates that this glycosylation pattern is a basic feature of ruminants and could have evolved simultaneously with the synepitheliochorial placental type which requires BNC. At the same time (50–55 million years ago) a repeated gene duplication and diversification of “modern” type PAGs, which are exclusively expressed in BNC, took place [55]. These “modern” PAGs are the main carriers of this specific type of glycosylation [46,47]. Given that glycosylation patterns of trophoblast can be very variable between species with epitheliochorial placentation [56], the conserved nature of BNC glycans suggests that PAG glycosylation has an important function, which may be related to the remarkable success of ruminants as a taxon.

Back to Article Outline

References 

  1. Wooding P, Burton G. Comparative placentation: structures, functions and evolution. Berlin, Heidelberg: Springer; 2008;pp. 301
  2. Vogel P. The current molecular phylogeny of Eutherian mammals challenges previous interpretations of placental evolution. Placenta. 2005;26:591–596
  3. Mess A, Carter AM. Evolution of the placenta during the early radiation of placental mammals. Comp Biochem Physiol A Mol Integr Physiol. 2007;148:769–779
  4. Enders AC. Reasons for diversity of placental structure. Placenta. 2009;30(Suppl. A):S15–S18
  5. Price SA, Bininda-Emonds OR, Gittleman JL. A complete phylogeny of the whales, dolphins and even-toed hoofed mammals (Cetartiodactyla). Biol Rev Camb Philos Soc. 2005;80:445–473
  6. Agnarsson I, May-Collado LJ. The phylogeny of Cetartiodactyla: the importance of dense taxon sampling, missing data, and the remarkable promise of cytochrome b to provide reliable species-level phylogenies. Mol Phylogenet Evol. 2008;48:964–985
  7. Klisch K, Mess A. Evolutionary differentiation of cetartiodactyl placentae in the light of the viviparity-driven conflict hypothesis. Placenta. 2007;28:353–360
  8. Wooding FB, Kimura J, Fukuta K, Forhead AJ. A light and electron microscopical study of the tragulid (mouse deer) placenta. Placenta. 2007;28:1039–1048
  9. Wooding FB. Current topic: the synepitheliochorial placenta of ruminants: binucleate cell fusions and hormone production. Placenta. 1992;13:101–113
  10. Wooding FB, Beckers JF. Trinucleate cells and the ultrastructural localisation of bovine placental lactogen. Cell Tissue Res. 1987;247:667–673
  11. Wooding FB, Morgan G, Forsyth IA, Butcher G, Hutchings A, Billingsley SA, et al. Light and electron microscopic studies of cellular localization of oPL with monoclonal and polyclonal antibodies. J Histochem Cytochem. 1992;40:1001–1009
  12. Wooding FB, Roberts RM, Green JA. Light and electron microscope immunocytochemical studies of the distribution of pregnancy associated glycoproteins (PAGs) throughout pregnancy in the cow: possible functional implications. Placenta. 2005;26:807–827
  13. Munson L, Kao JJ, Schlafer DH. Characterization of glycoconjugates in the bovine endometrium and chorion by lectin histochemistry. J Reprod Fertil. 1989;87:509–517
  14. Lehmann M, Russe I, Sinowatz F. [Detection of lectin binding sites in the trophoblast of cattle during early pregnancy], Anat Histol Embryol. 1992;21:263–270
  15. Jones CJ, Koob B, Stoddart RW, Hoffmann B, Leiser R. Lectin-histochemical analysis of glycans in ovine and bovine near-term placental binucleate cells. Cell Tissue Res. 1994;278:601–610
  16. Nakano H, Shimada A, Imai K, Takahashi T, Hashizume K. Association of Dolichos biflorus lectin binding with full differentiation of bovine trophoblast cells. Reproduction. 2002;124:581–592
  17. Klisch K, Leiser R. In bovine binucleate trophoblast giant cells, pregnancy-associated glycoproteins and placental prolactin-related protein-I are conjugated to asparagine-linked N-acetylgalactosaminyl glycans. Histochem Cell Biol. 2003;119:211–217
  18. Maddox PH, Jenkins D. 3-Aminopropyltriethoxysilane (APES): a new advance in section adhesion. J Clin Pathol. 1987;40:1256–1257
  19. Jones CJ, Abd-Elnaeim M, Bevilacqua E, Oliveira LV, Leiser R. Comparison of uteroplacental glycosylation in the camel (Camelus dromedarius) and alpaca (Lama pacos). Reproduction. 2002;123:115–126
  20. Baldus SE, Thiele J, Park YO, Hanisch FG, Bara J, Fischer R. Characterization of the binding specificity of Anguilla anguilla agglutinin (AAA) in comparison to Ulex europaeus agglutinin I (UEA-I). Glycoconj J. 1996;13:585–590
  21. Lotan R, Sharon N. Peanut (Arachis hypogaea) agglutinin. Methods Enzymol. 1978;50:361–367
  22. Sueyoshi S, Tsuji T, Osawa T. Carbohydrate-binding specificities of five lectins that bind to O-Glycosyl-linked carbohydrate chains. Quantitative analysis by frontal-affinity chromatography. Carbohydr Res. 1988;178:213–224
  23. Debray H, Montreuil J. Aleuria aurantia agglutinin. A new isolation procedure and further study of its specificity towards various glycopeptides and oligosaccharides. Carbohydr Res. 1989;185:15–26
  24. Wu AM, Song SC, Wu JH, Kabat EA. Affinity of Bandeiraea (Griffonia) simplicifolia lectin-I, isolectin B4 for Gal alpha 1–>4 Gal ligand. Biochem Biophys Res Commun. 1995;216:814–820
  25. Piller V, Piller F, Cartron JP. Comparison of the carbohydrate-binding specificities of seven N-acetyl-D-galactosamine-recognizing lectins. Eur J Biochem. 1990;191:461–466
  26. Wu AM, Wu JH, Watkins WM, Chen CP, Song SC, Chen YY. Differential binding of human blood group Sd(a+) and Sd(a−) Tamm-Horsfall glycoproteins with Dolichos biflorus and Vicia villosa-B4 agglutinins. FEBS Lett. 1998;429:323–326
  27. Crowley JF, Goldstein IJ, Arnarp J, Lonngren J. Carbohydrate binding studies on the lectin from Datura stramonium seeds. Arch Biochem Biophys. 1984;231:524–533
  28. Yamashita K, Totani K, Ohkura T, Takasaki S, Goldstein IJ, Kobata A. Carbohydrate binding properties of complex-type oligosaccharides on immobilized Datura stramonium lectin. J Biol Chem. 1987;262:1602–1607
  29. De Boeck H, Loontiens FG, Lis H, Sharon N. Binding of simple carbohydrates and some N-acetyllactosamine-containing oligosaccharides to Erythrina cristagalli agglutinin as followed with a fluorescent indicator ligand. Arch Biochem Biophys. 1984;234:297–304
  30. Shibuya N, Goldstein IJ, Van Damme EJ, Peumans WJ. Binding properties of a mannose-specific lectin from the snowdrop (Galanthus nivalis) bulb. J Biol Chem. 1988;263:728–734
  31. Iskratsch T, Braun A, Paschinger K, Wilson IB. Specificity analysis of lectins and antibodies using remodeled glycoproteins. Anal Biochem. 2009;386:133–146
  32. Nachbar MS, Oppenheim JD. Lectins in the United States diet: a survey of lectins in commonly consumed foods and a review of the literature. Am J Clin Nutr. 1980;33:2338–2345
  33. Pereira ME, Kabat EA. Specificity of purified hemagglutinin (lectin) from lotus tetragonolobus. Biochemistry. 1974;13:3184–3192
  34. Debray H, Decout D, Strecker G, Spik G, Montreuil J. Specificity of twelve lectins towards oligosaccharides and glycopeptides related to N-glycosylproteins. Eur J Biochem. 1981;117:41–55
  35. Yan L, Wilkins PP, Alvarez-Manilla G, Do SI, Smith DF, Cummings RD. Immobilized Lotus tetragonolobus agglutinin binds oligosaccharides containing the Le(x) determinant. Glycoconj J. 1997;14:45–55
  36. Wang WC, Cummings RD. The immobilized leukoagglutinin from the seeds of Maackia amurensis binds with high affinity to complex-type Asn-linked oligosaccharides containing terminal sialic acid-linked alpha-2,3 to penultimate galactose residues. J Biol Chem. 1988;263:4576–4585
  37. Sarkar M, Wu AM, Kabat EA. Immunochemical studies on the carbohydrate specificity of Maclura pomifera lectin. Arch Biochem Biophys. 1981;209:204–218
  38. Irimura T, Nicolson GL. Interaction of pokeweed mitogen with poly(N-acetyllactosamine)-type carbohydrate chains. Carbohydr Res. 1983;120:187–195
  39. Yamaguchi K, Mori A, Funatsu G. Amino acid sequence and some properties of lectin-D from the roots of pokeweed (Phytolacca americana). Biosci Biotechnol Biochem. 1996;60:1380–1382
  40. Kaneda Y, Whittier RF, Yamanaka H, Carredano E, Gotoh M, Sota H, et al. The high specificities of Phaseolus vulgaris erythro- and leukoagglutinating lectins for bisecting GlcNAc or beta 1-6-linked branch structures, respectively, are attributable to loop B. J Biol Chem. 2002;277:16928–16935
  41. Bhattacharyya L, Haraldsson M, Brewer CF. Precipitation of galactose-specific lectins by complex-type oligosaccharides and glycopeptides: studies with lectins from Ricinus communis (agglutinin I), Erythrina indica, Erythrina arborescens, Abrus precatorius (agglutinin), and Glycine max (soybean). Biochemistry. 1988;27:1034–1041
  42. Jones CJ, Morrison CA, Stoddart RW. Histochemical analysis of rat testicular glycoconjugates. 2. Beta-galactosyl residues in O- and N-linked glycans in seminiferous tubules. Histochem J. 1992;24:327–336
  43. Milosavljevic M, Duello TM, Schuler LA. In situ localization of two prolactin-related messenger ribonucleic acids to binucleate cells of bovine placentomes. Endocrinology. 1989;125:883–889
  44. Byatt JC, Warren WC, Eppard PJ, Staten NR, Krivi GG, Collier RJ. Ruminant placental lactogens: structure and biology. J Anim Sci. 1992;70:2911–2923
  45. Carvalho AF, Klisch K, Miglino MA, Pereira FT, Bevilacqua E. Binucleate trophoblast giant cells in the water buffalo (Bubalus bubalis) placenta. J Morphol. 2006;267:50–56
  46. Klisch K, Jeanrond E, Pang PC, Pich A, Schuler G, Dantzer V, et al. A tetraantennary glycan with bisecting N-acetylglucosamine and the Sd(a) antigen is the predominant N-glycan on bovine pregnancy-associated glycoproteins. Glycobiology. 2008;18:42–52
  47. Klisch K, De Sousa NM, Beckers JF, Leiser R, Pich A. Pregnancy associated glycoprotein-1, -6, -7, and -17 are major products of bovine binucleate trophoblast giant cells at midpregnancy. Mol Reprod Dev. 2005;71:453–460
  48. Barbato O, Sousa NM, Klisch K, Clerget E, Debenedetti A, Barile VL, et al. Isolation of new pregnancy-associated glycoproteins from water buffalo (Bubalus bubalis) placenta by Vicia villosa affinity chromatography. Res Vet Sci. 2008;85:457–466
  49. Kiewisz J, Sousa NM, Beckers JF, Panasiewicz G, Gizejewski Z, Szafranska B. Identification of multiple pregnancy-associated glycoproteins (PAGs) purified from the European bison (Eb; Bison bonasus L.) placentas. Anim Reprod Sci. 2009;112:229–250
  50. Kiewisz J, Sousa NM, Beckers JF, Vervaecke H, Panasiewicz G, Szafranska B. Isolation of pregnancy-associated glycoproteins from placenta of the American bison (Bison bison) at first half of pregnancy. Gen Comp Endocrinol. 2008;155:164–175
  51. Ropstad E, Johansen O, King C, Dahl E, Albon SD, Langvatn RL, et al. Comparison of plasma progesterone, transrectal ultrasound and pregnancy specific proteins (PSPB) used for pregnancy diagnosis in reindeer. Acta Vet Scand. 1999;40:151–162
  52. Klisch K, Boos A, Friedrich M, Herzog K, Feldmann M, Sousa N, et al. The glycosylation of pregnancy-associated glycoproteins and prolactin-related protein-I in bovine binucleate trophoblast giant cells changes before parturition. Reproduction. 2006;132:791–798
  53. Byatt JC, Welply JK, Leimgruber RM, Collier RJ. Characterization of glycosylated bovine placental lactogen and the effect of enzymatic deglycosylation on receptor binding and biological activity. Endocrinology. 1990;127:1041–1049
  54. Schachter H. Biosynthetic controls that determine the branching and microheterogeneity of protein-bound oligosaccharides. Biochem Cell Biol. 1986;64:163–181
  55. Telugu BP, Walker AM, Green JA. Characterization of the bovine pregnancy-associated glycoprotein gene family–analysis of gene sequences, regulatory regions within the promoter and expression of selected genes. BMC Genomics. 2009;10:185
  56. Jones CJP, Aplin JD. Glycans as attachment and signalling molecules at the fetomaternal interface. In: Signal Molecules in Animal and Human Gestation—Paulesu L, ed. (2004) Kerala: Research Signpost. 65–85.

PII: S0143-4004(09)00345-2

doi:10.1016/j.placenta.2009.11.001

Placenta
Volume 31, Issue 1 , Pages 11-17, January 2010

Article Tools

* Image Usage & Resolution