The distribution of receptors for Dolichos biflorus agglutinin (DBA) was studied by histochemical staining of paraffin sections with HRP- or FITC-DBA in mouse embryos at stages ranging from 4·5 to 12·5 days post coitum. Preimplantation blastocysts did not express DBA receptors. The receptors first appeared in primitive endoderm cells in 5-day embryos. In 5·5- to 7·5-day embryos, both the parietal and extraembryonic visceral endoderm cells expressed the receptors. Reichert's membrane was negative for DBA receptors. The columnar cells of the embryonic visceral endoderm (EVE) strongly expressed the receptors, while the flat cells at the antimesometrial pole of the EVE were negative or patchily positive. In 8- to 9-day embryos, the receptors were expressed in the epithelium of the fore- and hindgut. In 9·5- to 12·5-day embryos, the epithelial cells of various regions of the gut expressed the receptors, although the endodermal cells of the liver and the pancreas, both derived from the foregut, did not express them. In 8- to 12·5-day embryos both the visceral and parietal yolk sac endoderm were positive in DBA receptors. The receptors were localized exclusively on the free surface facing the yolk cavity or on the luminal surface and subjacent cytoplasm. All endodermal cells which were positive are known to have absorptive activity. All other tissues in these stages were negative in DBA receptors.

Cell surface and extracellular material have been assigned an important role in embryonic morphogenesis. Cell surface carbohydrates and lectin binding sites are known to be greatly altered during early embryogenesis in the mouse (Muramatsu et al. 1978; 1979; Stern et al 1978; Solter & Knowles, 1978; Kapadia, Feizi & Evans, 1980; Searle & Jenkinson, 1978; Wartiovaara, Leivo & Vaheri, 1979). Although the function of these surface molecules in morphogenesis is not well understood, lectins and antibodies recognizing certain terminal sugar sequences can be conveniently used to distinguish and trace particular populations of cells in morphogenesis (Sobel & Nebel, 1978; Chávez & Enders, 1981).

Receptors for Dolichos biflorus agglutinin (DBA), a lectin specific for terminal D-N-acetylgalactosamine (Etzler, 1972), were found to be expressed on stem cells and primitive endodermal cells of teratocarcinoma but not in variety of other differentiated cells derived from them in vitro (Muramatsu, Muramatsu & Ozawa, 1981).

Therefore, we are interested in the behaviour of the DBA receptor sites in normal postimplantation development when the three germ layers are formed and organogenesis begins.

In this report, the expression of DBA receptors in mouse embryos from 4·5 to 12·5 days post coitum (p.c.) was investigated by a fluorescent isothiocyanate or peroxidase-labelled DBA staining technique. DBA receptors were exclusively found in those endodermal cells showing absorptive activity.

Mouse embryos

Embryos from 129/Sv-SlCP and C57BL/10 strains mice were used. Copulation was determined by the presence of a vaginal plug. The middle of the ‘artificial night’ was designated as day 0 of pregnancy. The stages of the embryos ranged from 4·5 to 12·5 days p.c. Five to eight embryos of each strain at each stage were used for each DBA staining and control.

Lectins

DBA labelled with fluorescein isothiocyanate (FITC-DBA, OD 495/ 280 ratio = 1·05) or with horseradish peroxidase(HRP-DBA) were the products of E.Y. Lab., San Mateo, Cal., U.S.A.

Haptenic Sugar

D-7V-acetylgalactosamine (GalNAc) was the product of Nakarai Chemical Co., Japan.

Preparation of specimen

Whole uterus of 4·5–5 days p.c., uterine swelling of 5·5 – 8·5 days and the whole embryos of 9·5–12·5 days were recovered and immediately fixed in cold 95% ethanol for 24 h. They were dehydrated with ethanol, soaked in xylol, embedded in paraffin and serially sectioned as 6 μ m.

Staining

All the sections of a single embryo were subjected to experimental staining or to control staining when the stage was from 4·5 to 8·5 days p.c. A part of the sections from a single embryo was used for experimental staining and another part for control staining when the stage was from 9·5 to 12·-5 days p.c.

(i) Staining with HRP-DBA

Specimens were immersed in methanol-0·3% H2O2 for 30 min to block the activity of intrinsic peroxidase and washed with Dulbecco’s phosphate-buffered saline (DPBS). Subsequently, they were incubated in a dilute solution of HRP-lectin (100 μg/ml in DPBS) for 30 min at room temperature in a moist chamber. After incubation, each section was washed thoroughly in DPBS and stained with 3,3’-diamino azobenzidine (DAB) in 0·05 M-tris-HCl, pH 7·6. Some sections were stained with haematoxylin.

(ii) Staining with FITC-DBA

Deparaffinized sections were incubated with FITC-DBA (100 μg/ml in DPBS) for 30 min in a moist chamber. Subsequently, they were washed in DPBS thoroughly and mounted in fresh DPBS. The specimen was observed using an Olympus fluorescence microscope equipped with a mercury lamp HBO 200W and Olympus filter system BV and Y-50.

(iii) Control Staining

Specimens were incubated with HRP-DBA or FITC-DBA diluted in DPBS containing 0·2 M-GalNAc. All other procedures in control staining were the same as those in experimental staining.

The distribution of DBA binding sites was investigated by staining with HRP- or FITC-DBA in mouse embryos at developmental stages ranging from 4· 5 to 12·5 days p.c. The results of HRP-DBA stain were apparently identical to those of FITC-DBA on each stage. Therefore, the results will be documented by using the sections stained with HRP-DBA, since the structural presentation is better in HRP-DBA stained sections than in FITC-DBA stained ones.

As summarized in Table 1, DBA receptors were detected only on the cells of endodermal lineage in both 129/Sv-SlCP and C57BL/10 strains mice. DBA receptors were present in the parietal endoderm at every stage examined. Reichert’s membrane was DBA receptor negative. In the visceral endoderm, the extent of expression of DBA receptors varied with stage. Precise observation on each stage will be described below.

Table 1.

Localization of DBA receptors in the three germ layers and their derivatives in postimplantation mouse embryos ranging from 4·5 to 12·5 days p.c.

Localization of DBA receptors in the three germ layers and their derivatives in postimplantation mouse embryos ranging from 4·5 to 12·5 days p.c.
Localization of DBA receptors in the three germ layers and their derivatives in postimplantation mouse embryos ranging from 4·5 to 12·5 days p.c.

4·5- to 5-day embryos

Some blastocysts were in preimplantation stage and others were beginning implantation in 4·5 days p.c. Some of them have differentiated the primitive endoderm cells. All 4·5-days blastocysts were negative for DBA receptors (Fig. 1). DBA receptors were first recognized in the primitive endoderm cells only weakly in 5-day embryos. Both trophoblast and the embryonic ectoderm were negative for the receptors.

Fig. 1.

Absence of DBA receptors in the 4·5-day embryo in the uterus. HRP-DBA stain. 40 × 3·3. This blastocyst is peri-implantation stage, and some primitive endoderm cells have been formed already (→). DBA receptors are not expressed in both the embryoblast (E) and the trophectoderm (TE).

Fig. 1.

Absence of DBA receptors in the 4·5-day embryo in the uterus. HRP-DBA stain. 40 × 3·3. This blastocyst is peri-implantation stage, and some primitive endoderm cells have been formed already (→). DBA receptors are not expressed in both the embryoblast (E) and the trophectoderm (TE).

5·5- to 6·5-day embryos

After the formation of the visceral and parietal endoderm in 5·5-day embryos, DBA receptors had a patchy distribution in both types of endodermal layers. The lectin receptors appeared to be located in the cytoplasm (Fig. 2). In 6-5-day embryos the extraembryonic visceral endoderm cells were tall and columnar (Fig. 3). In these cells, the receptors were strongly expressed on the free surface facing the yolk cavity, but not on the surface facing the extraembryonic ectoderm. At this stage, the embryonic visceral endoderm cells become flat, and DBA receptors were rather weakly expressed on the free surface of these cells. On the other hand, the columnar ones near the extraembryonic visceral endoderm stained strongly. All other cells of the egg cylinder and trophoblasts were negative for DBA receptors.

Fig. 2.

Localization of DBA receptors in the 5·5-day embryo in the uterus. HRP-DBA stain with haematoxylin post staining. 40 × 5. DBA receptors have a patchy distribution (→) in both the visceral endoderm (VE) and the parietal endoderm (PE). Some cells stain only weakly (→). Receptors can be seen both on the cell surface and in the cytoplasm. Both the extraembryonic (EXEC) and the embryonic (EEC) ectoderm are negative for DBA receptors.

Fig. 2.

Localization of DBA receptors in the 5·5-day embryo in the uterus. HRP-DBA stain with haematoxylin post staining. 40 × 5. DBA receptors have a patchy distribution (→) in both the visceral endoderm (VE) and the parietal endoderm (PE). Some cells stain only weakly (→). Receptors can be seen both on the cell surface and in the cytoplasm. Both the extraembryonic (EXEC) and the embryonic (EEC) ectoderm are negative for DBA receptors.

Fig. 3.

Localization of DBA receptors in the 6·5-day embryo in the decidua. HRP-DBA stain. 10 × 3·3. Both the extraembryonic visceral (EXVE) and the parietal (PE) endoderm cells are positive for DBA receptors (→). In the embryonic visceral endoderm (EVE), the columnar cells stain strongly (→), but the flat cells stain only weakly. The EXEC and EEC ectoderm cells, Reichert’s membrane (RM) and trophoblast (TR) are negative for DBA receptors.

Fig. 3.

Localization of DBA receptors in the 6·5-day embryo in the decidua. HRP-DBA stain. 10 × 3·3. Both the extraembryonic visceral (EXVE) and the parietal (PE) endoderm cells are positive for DBA receptors (→). In the embryonic visceral endoderm (EVE), the columnar cells stain strongly (→), but the flat cells stain only weakly. The EXEC and EEC ectoderm cells, Reichert’s membrane (RM) and trophoblast (TR) are negative for DBA receptors.

7- to 7·5-day embryos

In 7- to 7·5-day embryos in which mesoderm formation has begun, the extraembryonic visceral endoderm cells stained strongly (Fig. 4, 5). In these cases, the free cell surface stained. On the other hand, the embryonic visceral endoderm cells in 7-day embryos still remained as flat as those of 6·5-day embryos, and either stained weakly or did not stain at all. In 7-5-day embryos, some cells of the embryonic visceral endoderm stained as strongly as the extraembryonic visceral endoderm cells, but such cells were rare. The parietal endoderm cells did not stain so strongly as the extraembryonic visceral endoderm cells. The mesodermal cells, the amnion and the chorion did not stain with DBA.

Fig. 4.

Localization of DBA receptors in the 7-day embryo in the decidua. HRP-DBA stain. 10 × 5. Localization of DBA receptors is almost the same as that in the 6-5-day embryo in Fig. 3. (→). Note the heavy stain on the free surface of the columnar cells of EVE (→). Mesoderm (M) is negative.

Fig. 4.

Localization of DBA receptors in the 7-day embryo in the decidua. HRP-DBA stain. 10 × 5. Localization of DBA receptors is almost the same as that in the 6-5-day embryo in Fig. 3. (→). Note the heavy stain on the free surface of the columnar cells of EVE (→). Mesoderm (M) is negative.

Fig. 5.

Localization of DBA receptors in the 7·5-day embryo in the decidua. HRP-DBA stain. 10 × 5. The columnar cells in the EXVE and EVE and some of the flat cells in EVE stain strongly (→). Note distinct stain on the free surface of these cells facing yolk cavity (YC). The neural plate (N), mesoderm (M) and the extra-embryonic membranes such as the amnion (A) or the chorion (C) are negative.

Fig. 5.

Localization of DBA receptors in the 7·5-day embryo in the decidua. HRP-DBA stain. 10 × 5. The columnar cells in the EXVE and EVE and some of the flat cells in EVE stain strongly (→). Note distinct stain on the free surface of these cells facing yolk cavity (YC). The neural plate (N), mesoderm (M) and the extra-embryonic membranes such as the amnion (A) or the chorion (C) are negative.

8- to 8·5-day embryos

At these age, the foregut pocket and the hindgut pocket have begun to form and become deeper. The luminal surface of the columnar cells of the foregut and the hindgut expressed the receptors more intensively than those of the endodermal cells on the outside of the embryos (Fig. 6, 7). The visceral yolk sac (VYS) and parietal yolk sac (PYS) endoderm cells also remained strongly positive for DBA receptors. The stained part was confined to the surface lining the yolk cavity. At larger magnification one could see that DBA receptors were distributed around both the rough surface of VYS cells and rather smooth surface of PYS cells. A large number of heavily stained vesicles were also observed in the apical cytoplasm of VYS endoderm cells (Fig. 8). Blood islands, the allantois, and other mesodermal and ectodermal cells were all negative.

Fig. 6.

Localization of DBA receptors in the foregut pocket in the 8·5-day embryo. HRP-DBA stain. 10 × 5. Note appearance of DBA receptors on the luminal surface of the endoderm cells near the opening of the foregut pocket (FG) (→). Both the visceral yolk sac (VYS) and parietal yolk sac (PYS) endoderm cells stain strongly. Other primitive organs such as somites (SM), the heart (H), (A) and (TR) are negative.

Fig. 6.

Localization of DBA receptors in the foregut pocket in the 8·5-day embryo. HRP-DBA stain. 10 × 5. Note appearance of DBA receptors on the luminal surface of the endoderm cells near the opening of the foregut pocket (FG) (→). Both the visceral yolk sac (VYS) and parietal yolk sac (PYS) endoderm cells stain strongly. Other primitive organs such as somites (SM), the heart (H), (A) and (TR) are negative.

Fig. 7.

Localization of DBA receptors in the hindgut pocket in the 8·-5-day embryo. HRP-DBA stain. 10 × 5. DBA receptors appear on the luminal surface of the endoderm near the opening of the hindgut pocket (HG) (→). The embryonic endoderm cells on the outside are still negative. Both VYS and PYS endoderm cells stain strongly. The allantois (AL), amnion (A), the neural tube (NT) and mesoderm (M) are negative.

Fig. 7.

Localization of DBA receptors in the hindgut pocket in the 8·-5-day embryo. HRP-DBA stain. 10 × 5. DBA receptors appear on the luminal surface of the endoderm near the opening of the hindgut pocket (HG) (→). The embryonic endoderm cells on the outside are still negative. Both VYS and PYS endoderm cells stain strongly. The allantois (AL), amnion (A), the neural tube (NT) and mesoderm (M) are negative.

Fig. 8.

Localization of DBA receptors in both VYS and PYS endoderm at larger magnification. HRP-DBA stain. 40 × 5. DBA receptors are strongly expressed around both the rough cell surface of VYS endoderm and rather smooth surface of PYS endoderm. Note a large number of heavily stained vesicles (○) in the apical cytoplasm of VYS endoderm cells. Reichert’s membrane (RM) and the blood islands (BI) are negative.

Fig. 8.

Localization of DBA receptors in both VYS and PYS endoderm at larger magnification. HRP-DBA stain. 40 × 5. DBA receptors are strongly expressed around both the rough cell surface of VYS endoderm and rather smooth surface of PYS endoderm. Note a large number of heavily stained vesicles (○) in the apical cytoplasm of VYS endoderm cells. Reichert’s membrane (RM) and the blood islands (BI) are negative.

9- to 12·5-day embryos

In these stages, new interactions occur in the three germ layers and organ rudiments emerge and organogenesis is in progress. Even in these stages, positive cells were confined to tissues of endodermal lineage. In 9-day embryos, the fore- and hindgut form a continuous tube, although the midgut remains open to the yolk cavity in the middle of the embryo. DBA receptors were strongly labelled in the columnar epithelium extruding from the portal region to the floor of the fore- and hindgut. On the other hand, DBA receptors were still negative in the flat cells of the dorsal epithelium of these fore- and hindgut (Fig. 9).

Fig. 9.

Localization of DBA receptors in the hindgut in the 9-day embryo. HRP-DBA stain. 10 × 5. DBA receptors are expressed on the hindgut columnar epithelium (→) extruding from the portal region (IP) to the floor of the hindgut. The VYS and PYS endoderm cells are positive in DBA receptors. The flat cells of the dorsal epithelium of the hindgut are still negative. Other tissues such as NT, AL, TR and BI are negative.

Fig. 9.

Localization of DBA receptors in the hindgut in the 9-day embryo. HRP-DBA stain. 10 × 5. DBA receptors are expressed on the hindgut columnar epithelium (→) extruding from the portal region (IP) to the floor of the hindgut. The VYS and PYS endoderm cells are positive in DBA receptors. The flat cells of the dorsal epithelium of the hindgut are still negative. Other tissues such as NT, AL, TR and BI are negative.

In 9·5- to 12·5-day embryos the fore- and hindgut undergo transformation into various kinds of digestive organs and the derivative organs such as lung and thyroid. In these stages, DBA receptors were expressed in the columnar epithelium of the various gut regions (Fig. 10). The luminal free surface was positive, but not so strongly as that of adult intestine. All other endodermal epithelial cells such as those of the primitive liver, pancreas and lung were negative for DBA receptors. Other tissues positive for DBA receptors were VYS and PYS endoderm. Again, only the luminal free surface stained strongly and the superficial cytoplasm contained DBA-positive granules.

Fig. 10A.

Localization of DBA receptors in the gut in the 11·5-day embryo. HRP-DBA stain with haematoxylin poststaining. 10 × 5. DBA receptors are localized in the intestinal epithelium (IE) (→). The mesenchyme (MC) and other tissues are negative. Fig. 10B. Localization of DBA receptors in the 11·5-day intestinal epithelium at larger magnification. HRP-DBA stain. 40 × 5. DBA receptors are seen on the luminal cell surface of intestinal epithelial cells (→). The mesenchyme is negative.

Fig. 10A.

Localization of DBA receptors in the gut in the 11·5-day embryo. HRP-DBA stain with haematoxylin poststaining. 10 × 5. DBA receptors are localized in the intestinal epithelium (IE) (→). The mesenchyme (MC) and other tissues are negative. Fig. 10B. Localization of DBA receptors in the 11·5-day intestinal epithelium at larger magnification. HRP-DBA stain. 40 × 5. DBA receptors are seen on the luminal cell surface of intestinal epithelial cells (→). The mesenchyme is negative.

The mesodermal tissues such as the primitive heart or kidney and the ectodermal tissues such as the primitive epidermis or nervous tissues were all negative.

Control

The specificity of the reaction was confirmed by preincubation of lectin with N-acetylgalactosamine. All specimens of the embryos at the stages ranging from 4·5 to 12·5 days p.c. were unstained (Fig. 11).

Fig. 11.

An example of control staining of DBA receptors. The 7-day embryo stained by HRP-DBA with GalNAc. 20 × 3·3. All cells are unstained.

Fig. 11.

An example of control staining of DBA receptors. The 7-day embryo stained by HRP-DBA with GalNAc. 20 × 3·3. All cells are unstained.

In mouse embryos at stages ranging from 4·5 to 12·5 days p.c., the cells positive for DBA receptors were those of endodermal lineage. Although in very primitive endoderm cells of blastocysts in peri-implantation stage the receptors were almost negative, the receptors were expressed, with increasing developmental age, on the primitive endoderm cells, on the extraembryonic visceral endoderm cells, on some of the embryonic visceral endoderm cells, on the parietal endoderm, and on VYS and PYS endoderm, and finally on some of the primitive gut epithelia. During early uterine life, DBA receptors were rarely detected on the cells of either ectodermal or mesodermal lineages. Although most of these cells of endodermal lineage possessed receptors, intensity and cellular localization of the DBA receptors varied with cell type.

Electron microscopical observations have suggested that embryonic and extraembryonic visceral endoderm cells have intensive absorptive and nutritional functions (Solter, Damjanov & Škreb, 1970; Batten & Haar, 1979). Numerous pinocytotic vacuoles, microvilli, primary and secondary lysosomes, and fair amounts of rough endoplasmic reticulum and free ribosomes are the most important characteristics of these cells. Endoderm cells of VYS contain specialized endocytic systems and microvilli lining the yolk cavity (Lambson, 1966; Schlüter, 1978; Takeuchi, 1980). Ultrastructurally PYS endoderm cells appear spherical or oval, with regular and smooth outlines, microvilli being absent until the middle stage of gestation (Jollie, 1968; Jensh et al., 1977). The endocytic systems on the surface and in the subjacent cytoplasm of these cells suggest that these cells phagocytose the material which passes through Reichert’s membrane from the maternal blood (Jollie, 1968; Carpenter, 1980).

Results documented in this communication reveal that DBA receptors are present most strongly on the luminal surface of these cells and in their apical cytoplasm which contain the endocytic systems. The intensity of the expression in PYS endoderm was not so strong as VYS endoderm. This might be due to the absence of well developed microvilli in PYS endoderm cells.

As the mesoderm formation advances, the embryonic visceral endoderm cells become flattened and depleted of microvilli and of almost all endocytic systems (Solter et al. 1970).

This study shows that expression of DBA receptors is either patchy, weak or absent in this region, and that only the columnar cells near the extraembryonic visceral endoderm express DBA receptors. Therefore, it is possible that columnar cells positive for the DBA receptor migrate into the extraembryonic region rather than lose the receptor, and that negative cells in this region are undifferentiated definitive endoderm cells recruited from embryonic ectoderm (Snell & Stevens, 1975; Gardner, 1978; Hogan & Tilly, 1981).

As the epithelium of the fore- and hindgut derived from this definitive endoderm transforms into the gut epithelial cells, the absorptive organelles such as microvilli and endocytic systems appear on the luminal surface and the apical cytoplasm (Overton, 1965).

These results reveal that DBA receptors are expressed on the luminal surface of the gut epithelial cells. However, the intensity was not so strong as that seen in the adult intestine (Watanabe, Takeda, Urano & Muramatsu, 1982), which has a strong absorptive function (Cardell, Badenhauser & Porter, 1967; Ito, 1965). Thus, expression of DBA receptors paralleled exactly that of microvilli and endocytic system. In contrast to the gut epithelia, DBA receptors were not detected on parenchymal cells of the liver, lung and pancreas, all of which are derived from the foregut endoderm.

Thus in the early half of uterine life, DBA receptors are expressed exclusively on cells which are of endodermal origin, and have simultaneously an absorptive function.

This parallelism of DBA receptors and an absorptive function, however, does not hold true in cells of non-endodermal origins. For example, sperms, oocytes and the renal collecting tubules in adult mice (Watanabe, Muramatsu, Shirane & Ugai, 1981) and thymocytes in the 13th day foetuses (Kasai et al., 1980) have DBA receptors. These types of cells do not seem to have any specialized absorptive function. On the other hand the renal brush border which has an intense absorptive function does not possess DBA receptors (Watanabe et al. 1981).

During preimplantation stages a gradual fall in the extent of DBA receptor expression has been noticed. Fujimoto, Muramatsu, Urushihara & Yanagisawa (1982) studied distribution of DBA receptors on freshly flushed, unfixed cleaving eggs and early blastocysts. They found that cleaving embryos intensely express DBA receptors, and that the extent of staining becomes weaker in early blastocysts. We got similar results with embryos fixed in situ (Noguchi, M. unpublished). In late blastocysts, the receptors become undetectable by the histochemical method used in this report.

Many experimental data have suggested that stem cells of teratocarcinomas correspond to cells of embryonic ectoderm of early postimplantation embryos (Stevens, 1975; Evans, Lovell-Badge, Stern & Stinnakre, 1979; Martin, 1980; Noguchi & Kume, 1980). We have observed that stem cells of certain teratocarcinomas, such as F9 cells and core cells of teratocarcinoma OTT6050, strongly express DBA receptors (Muramatsu et al. 1981). However, the normal counterparts of teratocarcinoma stem cells were DBA negative. At present there is no explanation for the discrepancy in DBA receptor expression between the multipotential embryonic cells and teratocarcinoma stem cells.

The receptors expressed in teratocarcinomas are high-molecular-weight glycoproteins (Muramatsu et al. 1981; Ozawa, Yonesawa, Sato & Muramatsu, 1982). As DBA reactivity is merely a marker of the presence of a terminal sugar moiety (D-N-acetylgalactosamine), it is quite possible that DBA receptors found on those various type of tissues may be different glycoconjugates.

In any event, DBA receptors seem to be useful markers of absorptive cells of endodermal origin in early postimplantation embryos. This knowledge will be especially helpful in cell separation in early postimplantation embryos.

Batten
,
B. E.
&
Haar
,
J. L.
(
1979
).
Fine structural analysis of the effect of trypan blue on the visceral endoderm of the mouse egg cylinder
.
Acta Anat
.
105
,
256
268
.
Cardell
,
R. R.
, Jr
.,
Badenhausen
,
S.
&
Porter
,
K. R.
(
1967
).
Intestinal triglyceride absorption in the rat: an electron microscopical study
.
J. Cell Biol
.
34
,
123
155
.
Carpenter
,
S. J.
(
1980
).
Placental permeability during early gestation in the hamster. Electron microscopic observations using horseradish peroxidase as a macromolecular tracer
.
Anat. Rec
.
197
,
221
238
.
Chavez
,
D. J.
&
Enders
,
A. C.
(
1981
).
Temporal changes in lectin binding of peri-implantation mouse blastocysts
.
Devi Biol
.
87
,
267
276
.
Etzler
,
M.
(
1972
).
Horse gram (Dolichos biflorus) lectin
.
Methods Enzymol
.
28
,
340
344
.
Evans
,
M. J.
,
Lovell-Badge
,
R. H.
,
Stern
,
P. L.
&
Stinnakre
,
M. G.
(
1979
).
Cell lineages of the mouse embryo and embryonal carcinoma cells; Forssman antigen distribution and patterns of protein synthesis
.
INSERM Symposium No. 10
(ed.
N.
Le Douarin
), pp.
115
129
.
Elsevier
:
North-Holland Biomedical Press
.
Fujimoto
,
H.
,
Muramatsu
,
T.
,
Urushihara
,
H.
&
Yanagisawa
,
K. O.
(
1982
).
Receptors for Dolichos biflorus agglutinin: A new cell surface marker common to teratocarcinoma cells and preimplantation mouse embryos, Differentiation, (in the press)
.
Gardner
,
R. L.
(
1978
).
The relationship between cell lineage and differentiation in the early mouse embryo
.
Results and Problems in Cell Differentiation
(ed.
W. J.
Gehring
), vol.
9
, pp.
205
241
.
Hogan
,
B. L. M.
&
Tilly
,
R.
(
1981
).
Cell interactions and endoderm differentiation in cultured mouse embryos
.
J. Embryol. exp. Morph
.
62
,
379
394
.
Ito
,
S.
(
1965
).
The enteric surface coat on cat intestinal microvilli
.
J. Cell Biol
.
27
,
475
491
.
Jensh
,
R. P.
,
Koszalka
,
T. R.
,
Jensen
,
M.
,
Biddle
,
L.
&
Brent
,
R. L.
(
1977
).
Morphologic alterations in the parietal yolk-sac of the rat from the 12th to the 19th day of gestation
.
J. Embryol. exp. Morph
.
39
,
9
21
.
Jollie
,
W. P.
(
1968
).
Changes in the fine structure of the parietal yolk sac of the rat placenta with increasing gestational age
.
Am. J. Anat
.
122
,
513
532
.
Kapadia
,
A.
,
Feizi
,
T.
&
Evans
,
M. J.
(
1980
).
Changes in the expression and polarization of blood group I and i antigens in postimplantation embryos and teratocarcinomas of mouse associated with cell differentiation
.
Expl Cell Res
.
131
,
185
195
.
Kasai
,
M.
,
Ochiai
,
Y.
,
Habu
,
S.
,
Muramatsu
,
T.
,
Tokunaga
,
T.
&
Okumura
,
K.
(
1980
).
A new differentiation marker selectively expressed on mouse fetal thymocytes
.
Immunol. Lett
.
2
,
157
158
.
Lambson
,
R. O.
(
1966
).
An electron microscopic visualization of transport across at visceral yolk sac
.
Am. J. Anat
.
118
,
21
30
.
Martin
,
G. R.
(
1980
).
Tetratocarcinomas and mammalian embryogenesis
.
Science, N. Y
.
209
,
768
776
.
Muramatsu
,
T.
,
Gachelin
,
G.
,
Damonneville
,
M.
,
Delarbre
,
C.
&
Jacob
,
F.
(
1979
).
Cell surface carbohydrates of embryonal carcinoma cells: polysaccharidic side chains of F9 antigens and of receptors to two lectins, FBP and PNA
.
Cell
18
,
183
191
.
Muramatsu
,
T.
,
Gachelin
,
G.
,
Nicolas
,
J. F.
,
Condamine
,
H.
,
Jakob
,
H.
&
Jacob
,
F.
(
1978
).
Carbohydrate structure and cell differentiation: unique properties of fucosyl glycopeptides isolated from embryonal carcinoma cells
.
Proc. natn. Acad. Sci., U.S.A
.
75
,
2315
2319
.
Muramatsu
,
T.
,
Muramatsu
,
H.
&
Ozawa
,
M.
(
1981
).
Receptors for Dolichos biflorus agglutinin on embryonal carcinoma cells
.
J. Biochem
.
89
,
473
481
.
Noguchi
,
M.
&
Kume
,
A.
(
1980
).
Equivalency of teratocarcinoma cells to 4|-day and 5-day embryonic cells
.
Develop. Growth Differ
.
22
,
715
.
Overton
,
J.
(
1965
).
Fine structure of the free cell surface in developing mouse intestinal mucosa
.
J. exp. Zook
,
159
,
195
202
.
Ozawa
,
M.
,
Yonezawa
,
S.
,
Sato
,
E.
&
Muramatsu
,
T.
(
1982
).
New glycoprotein antigen common to teratocarcinoma, visceral endoderm and renal tubular brush border
.
Devi Biol
.
91
,
351
359
.
Schluter
,
G.
(
1978
).
Ultrastructural changes of the early visceral yolk sac layer of mouse embryos after maternal injection of trypan blue
.
Anat. Embryol
.
153
,
287
293
.
Searle
,
R. F.
&
Jenkinson
,
E. J.
(
1978
).
Localization of trophoblast-defined surface antigens during early mouse embryogenesis
.
J. Embryol. exp. Morph
.
43
,
147
156
.
Snell
,
G. D.
&
Stevens
,
L. C.
(
1975
).
Early Embryology
.
Biology of the Laboratory Mouse
, 2nd ed. (ed.
E. L.
Green
), pp.
205
254
.
New York
:
Dover Publications Inc
.
Sobel
,
J. S.
&
Nebel
,
L.
(
1978
).
Changes in Concanavalin A agglutinability during development of the inner cell mass and trophoblast of mouse blastocysts in vitro
.
J. Reprod. Fert
.
52
,
239
248
.
Solter
,
D.
,
Damjanov
,
I.
&
ŠKreb
,
N.
(
1970
).
Ultrastructure of Mouse Egg-Cylinder
.
Z. Anat. Entwickl. Gesch
.
132
,
291
298
.
Solter
,
D.
&
Knowles
,
B. B.
(
1978
).
Monoclonal antibody defining a stage-specific mouse embryonic antigen (SSEA-1)
.
Proc. natn. Acad. Sci., U.S.A
.
75
,
5565
5569
.
Stern
,
P. L.
,
Willson
,
K. R.
,
Lennox
,
E.
,
Galfre
,
G.
,
Milstein
,
C.
,
Secher
,
D.
,
Ziegler
,
A.
&
Springer
,
T.
(
1978
).
Monoclonal antibodies as probes for differentiation and tumor-associated antigens: Forssman specificity on teratocarcinoma stem cells
.
Cell
14
,
775
783
.
Stevens
,
L. C.
(
1975
).
Comparative development of normal and parthenogenetic mouse embryos, early testicular and ovarian teratomas, and embryoid bodies
.
Teratomas and Differentiation
. (ed.
M.
Sherman
&
D.
Solter
), pp.
17
32
.
New York, London
:
Academic Press
.
Takeuchi
,
I. K.
(
1980
).
Lipid droplets in the visceral yolk sac endodermal cells of the postimplantation rat embryo: Application of malachite green-glutaradehyde fixative
.
Cell Tissue Res
.
209
,
29
41
.
Wartiovaara
,
J.
,
Leivo
,
I.
&
Vaheri
,
A.
(
1979
).
Expression of the cell surface-associated glycoprotein, fibronectin, in the early mouse embryo
.
Devi Biol
.
69
,
247
257
.
Watanabe
,
M.
,
Muramatsu
,
T.
,
Shirane
,
H.
&
Ugai
,
K.
(
1981
).
Discrete distribution of binding sites for Dolichos biflorus agglutinin (DBA) and for peanut agglutinin (PNA) in mouse organ tissues
.
J. Histochem. Cytochem
.
29
,
779
790
.
Watanabe
,
M.
,
Takeda
,
Z.
,
Urano
,
H.
&
Muramatsu
,
T.
(
1982
).
Lectins as reagents to detect differentiation-dependent alterations of carbohydrates
.
In Teratocarcinoma and Embryonic Cell Interactions
(ed.
Muramatsu
,
T.
,
Gachelin
,
G.
,
Moscona
,
A. A.
&
Ikawa
,
Y.
), pp.
217
228
.
Japan Scientific Society Press and Academic Press
.