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At least 19 recordsLinked to original sources
PubMed2004

The N-terminal prodomain of sV23 is essential for the assembly of a functional vitelline membrane network in Drosophila.

The vitelline membrane is a specialized extracellular matrix that surrounds and protects the oocyte. Recent studies indicate that it also serves as a storage site for embryonic pattern determinants. sV23, a major vitelline membrane protein, is essential for the morphogenesis of the vitelline membrane as sV23 protein null mutants lay flaccid, infertile eggs. By analyzing a series of sV23 mutant transgenes in the sV23 protein null genetic background, we have shown that sV23 is secreted as a proprotein in functional excess and that C- and N-terminal prodomains are removed successively, following its deposition in the extracellular space. Although a target site for subtilisin-like convertases is essential for N-terminal processing, N-terminal processing is not necessary for the assembly of a functional vitelline membrane layer. While C-terminal truncations were tolerated, the removal of N-terminal sequences lead to the production of flaccid, infertile eggs with a soluble, rather than insoluble, vitelline membrane network. We propose that the hydrophobic N-terminal prodomain plays an early and essential role in aligning molecules within the vitelline membrane network, much like hydrophobic domains within elastin drive the assembly and alignment of molecules within elastin-based extracellular matrices.

Amino Acid Sequence↗
PubMed1992

Isolation of a novel protein from the outer layer of the vitelline membrane.

The outer layer of the vitelline membrane from hen egg yolk consists of ovomucin, vitelline membrane outer layer protein I (VMOI) and lysozyme. Here we report the occurrence of a further basic protein (pI 11.5) in the outer layer, which was designated as vitelline membrane outer layer protein II (VMOII). It was dissociated from the outer layer in a 10% (w/v) NaCl solution and purified to homogeneity by ion-exchange chromatography. VMOII is a simple protein with a molecular mass of 6000 Da, as determined by sedimentation equilibrium analysis. The amino acid composition of VMOII was characterized by the absence of Met and high contents of cystine (half) (14%) and basic amino acids (6% Arg, 6% Lys and 3% His). Analysis of carboxymethylated VMOII indicated that all cysteine residues were involved in disulphide bonding, which appears to facilitate the binding of SDS to the protein. Sequence comparison of the N-terminal 20 residues revealed no identity with other known proteins. VMOII contained a small amount of alpha-helix and was quite resistant to heat denaturation.

Amino Acid Sequence↗
PubMed1986

Egg white lysozyme is the major protein of the hen's egg vitelline membrane.

Lysozyme accounts for 37% of the proteins of the hen's egg vitelline membrane. It can be extracted by salt solutions and purified by gel filtration on Sephadex G-50. There are no differences between the chemical and enzymic properties of egg white and vitelline membrane lysozymes. Vitelline membranes of ovarian eggs do not contain lysozyme. It is thus concluded that lysozyme is localized in the outer layer. Vitelline membranes from fertilized and unfertilized eggs contain the same amount of lysozyme; its percentage decreases after two days of incubation.

Amino Acids↗
PubMed1987

Characterization and sequence of follicle cell genes selectively expressed during vitelline membrane formation in Drosophila.

To isolate genes involved in vitelline membrane production, an ovarian cDNA library was screened with eggchamber RNAs labeled in vivo. Two cDNA clones encoding RNAs that are selectively expressed in follicle cells during the period of vitelline membrane formation were isolated. Following isolation of homologous genomic clones from a Drosophila library, one gene was localized by in situ hybridization to chromosomal region 26A, and the other to 3C. Developmental Northern blots demonstrated that both genes produce 700-800 nucleotide transcripts that accumulate during the stages of vitelline membrane synthesis. In vitro translation products from hybrid selected RNAs and DNA sequence analysis both indicate that the 26A region gene encodes a major protein component of the vitelline membrane. The structural properties of the 3C region follicle cell gene seem more compatible with an intracellular function.

Amino Acid Sequence↗
PubMed1996

Eggshell assembly in Drosophila: processing and localization of vitelline membrane and chorion proteins.

The Drosophila eggshell consists of three major proteinaceous layers: the vitelline membrane, the inner chorionic layer, and the outer endochorion. During the latter stages of oogenesis, the proteins that comprise these layers are synthesized and secreted by epithelial follicle cells which surround the maturing oocyte. While there is considerable knowledge of the structural units which comprise the eggshell layers, there is little knowledge of how individual proteins function or interact with one another to form the structure. Immunoelectron microscopy was used to follow the distribution of four different eggshell proteins in the assembling and mature eggshell. sV23 and sV17, follicle cell proteins synthesized during the early stages of eggshell formation (stages 8-10), were distributed within the vitelline membrane layer at all stages. Despite marked temporal differences in their accumulation profiles, s36 and s18, putative chorion proteins, were similarly distributed throughout the floor, pillars, and roof of the endochorion. Although the vitelline membrane appears to be morphologically complete by stage 11, developmental Western blots and immunolocalization data indicate that molecular dynamism persists within the layer throughout the subsequent choriogenic stages. During early chorion formation the vitelline membrane appears to act as a reservoir for chorion proteins since s36 was found predominantly in the vitelline membrane layer of stage 12 egg chambers. During the late choriogenic stages (13-14), both sV17 and sV23 are processed to smaller derivatives. Interactions between the eggshell layers were suggested by ultrastructural analysis of a sV23 protein null mutant which showed that the structural integrity of the outer chorion is dependent upon the presence of a vitelline membrane component.

Animals↗
PubMed2001

Drosophila vitelline membrane cross-linking requires the fs(1)Nasrat, fs(1)polehole and chorion genes activities.

Abstract. During the final step of Drosophila vitelline membrane formation, the structural proteins composing this layer become cross-linked by covalent bonds. In the present report, we analyzed the vitelline membrane cross-linking in mutants having defects either in this layer or in the chorionic layers. In the fs(1)Nasrat and fs(1)polehole mutant alleles conferring defects in vitelline membrane formation, disruption of vitelline membrane cross-linking was observed, indicating the involvement of these two genes in the process. On the contrary, in the fs(1)Nasrat and fs(1)polehole alleles showing defects only at the termini of the embryo the vitelline membrane is properly formed, confirming a multifunctional activity of their gene products. Altered vitelline membrane cross-linking was also detected in a mutant of the chorion protein gene Cp36and in the chorion amplification mutant fs(1)K1214, suggesting a role of the structural components of chorion layers in the process of vitelline membrane hardening.

Animals↗
PubMed1980

Ultrastructure of vitelline membranes from normal and mottled egg yolks.

This study showed that ultrastructure of the vitelline membrane degenerated with degree of yolk mottling. The more severe the mottling the greater the damage to the membrane. The vitelline membrane appears to be composed of three separate structures. The primary matrix (probably collagen) retains its composition until mottling is most severe; then this structure starts to come apart and lose its integrity. The secondary matrix (probably mucin) aids in holding the primary structure in a fixed position. When this structure is removed there is movement in the primary matrix causing large holes to appear. The tertiary matrix (also mucin) is the quickest to disintegrate. The tertiary matrix covers the other structures much like the cuticle around the egg shell. Once it is removed, the remaining structures are open to stress and damage as mottling increases.

Animals↗
PubMed1994

Crystallization and preliminary crystallographic data of vitelline membrane outer layer protein I, VMO-I.

The vitelline membrane outer layer protein I (VMO-I), which is isolated from the vitelline membrane outer layer of hen's eggs, has been crystallized from an acetate buffer solution by the hanging-drop method. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit cell dimensions a = 62.42 A, b = 110.52 A, c = 44.15 A. There are two molecules (M(r) = 18,000) per asymmetric unit. The crystals diffract to at least 2.2 A Bragg spacings.

Animals↗
PubMed1993

Comparative analysis of the sequence and structure of two Drosophila melanogaster genes encoding vitelline membrane proteins.

Two Drosophila melanogaster vitelline membrane protein-encoding genes (VM), located at polytene band positions 26A and 34C, have been cloned and comparatively characterized at the nucleotide level. Sequence analysis of genomic and cDNA clones for the two genes, VM26A.1 and VM34C.1, indicates that both are similarly organized with a central highly conserved domain [Scherer et al., Dev. Biol. 130 (1988) 786-788] which is flanked by unrelated regions, and that both genes lack introns. Comparison of the upstream regions reveals that both VM genes contain a hepatmeric element identical to one associated with the D. melanogaster yolk protein-encoding genes (YP). This heptamer occurs in the specific 5' flanking region responsible for ovarian temporal- and tissue-specific control in both VM and YP genes. A putative chorion transcription factor 2 site is also associated with an upstream control element of VM26A.1, but not with any sequenced portion of VM34C.1.

Amino Acid Sequence↗
PubMed1993

Proteins of the vitelline membrane of quail (Coturnix coturnix japonica) eggs.

Proteins in the vitelline membrane of quail (Coturnix coturnix japonica) eggs were analyzed by SDS-PAGE. Ten major bands, molecular mass ranging from 14.5 to 285 kDa, can be clearly distinguished. Two bands corresponding to the molecular masses of 33 and 175 kDa were detected in the inner layer of the membrane and both were stained with periodic acid-Schiff reagent, indicating that they are glycoproteins. Nine bands were detected in the outer layer of the membrane. Among them, 265- and 285-kDa bands were glycoproteins. During storage of eggs at 25 C, the yolk index significantly decreased. Among the 10 proteins of the vitelline membrane, a decrease in the 20-kDa protein was most prominent, disappearing after 5 days of storage. The 16.5- and 175-kDa protein bands were also less prominent, whereas the 40- and 61-kDa proteins increased during storage. These changes in the proteins of the vitelline membrane were also observed in eggs stored at 4 C, although the changes occurred more slowly than that noted from the eggs stored at 25 C.

Analysis of Variance↗
PubMed1961

Changes in the spermatozoon during fertilization in Hydroides hexagonus (Annelida). I. Passage of the acrosomal region through the vitelline membrane.

In the previous paper the structure of the acrosomal region of the spermatozoon was described. The present paper describes the changes which this region undergoes during passage through the vitelline membrane. The material used consisted of moderately polyspermic eggs of Hydroides hexagonus, osmium-fixed usually 9 seconds after insemination. There are essentially four major changes in the acrosome during passage of the sperm head through the vitelline membrane. First, the acrosome breaks open apically by a kind of dehiscence which results in the formation of a well defined orifice. Around the lips of the orifice the edges of the plasma and acrosomal membranes are then found to be fused to form a continuous membranous sheet. Second, the walls of the acrosomal vesicle are completely everted, and this appears to be the means by which the apex of the sperm head is moved through the vitelline membrane. The lip of the orifice comes to lie deeper and deeper within the vitelline membrane. At the same time the lip itself is made up of constantly changing material as first the material of the outer zone and then that of the intermediate zone everts. One is reminded of the lip of an amphibian blastopore, which during gastrulation maintains its morphological identity as a lip but is nevertheless made up of constantly changing cells, with constantly changing outline and even constantly changing position. Third, the large acrosomal granule rapidly disappears. This disappearance is closely correlated with a corresponding disappearance of a part of the principal material of the vitelline membrane from before it, and the suggestion is made that the acrosomal granule is the source of the lysin which dissolves this part of the vitelline membrane. Fourth, in the inner zone the fifteen or so short tubular invaginations of the acrosomal membrane, present in the normal unreacted spermatozoon, lengthen considerably to become a tuft of acrosomal tubules. These tubules are the first structures of the advancing sperm head to touch the plasma membrane of the egg. It is notable that the surface of the acrosomal tubules which once faced into the closed acrosomal cavity becomes the first part of the sperm plasma membrane to meet the plasma membrane of the egg. The acrosomal tubules of Hydroides, which arise simply by lengthening of already existing shorter tubules, are considered to represent the acrosome filaments of other species.

Acrosome↗
PubMed1977

Ultrastructural differentiations in the developing follicle cortex of Locusta migratoria, with special reference to vitelline membrane formation.

Electron microscopic studies on developing follicles of Locusta migratoria show the vitelline membrane to be composed of two ultrastructurally distinguishable components: The vitelline membrane bodies (VMBs) and, in addition, fine granular material, cementing the VMBs together. VMBs form first in the oocyte-near zone within the oocyte-follicle cell space. Subsequently, the second vitelline membrane substance is secreted between the VMBs through apical protrusions of the follicle cells. The possible origin of the VMBs is discussed. Yolk uptake in Locusta seems to occur predominantly by pinocytosis. During oocyte development the oocyte membrane is enlarged by numerous microvilli and folds. In addition pinocytotic vesicles are pinched off. It is supposed that the latter loose their coat and eventually transform into large proteid yolk spheres.

Animals↗
PubMed1975

Macromolecular components of the vitelline membrane of hen's egg. I. Membrane structure and its deterioration with age.

The vitelline membrane of hen's egg has been successfully solubilized in sodium dodecyl sulfate (SDS), guanidine hydrochloride and urea solutions, and its macromolecular components examined. SDS-gel electrophoresis of the membrane solution revealed the presence of three major components designated I, II, and III, all containing carbohydrate and protein. The approximate molecular weights of components I and II were 32,000 and 260,000, respectively, and the sedimentation coefficients were 2.2S and 4.3S. Component III was in an aggregated form which disintegrated into smaller components upon reduction with 2-mercaptoethanol. It was found that component II (4.3S component) deteriorated during storage of the egg with the concomitant formation of degraded components. The loss of this component was accompanied by a gradual decrease of the neutral sugar content of the vitelline membrane. On the basis of these data, the membrane structure and its deterioration during storage are discussed.

Aging↗
PubMed2005

Outgrowth of Salmonellae and the physical property of albumen and vitelline membrane as influenced by egg storage conditions.

This study was undertaken to determine the influence of storage time and temperature on the volume, weight, and pH of egg albumen, the physical strength of vitelline membrane, and the fate of Salmonella Enteritidis artificially inoculated into egg albumen. A fiber-optic probe was used for inoculation with Salmonella Enteritidis at 10(2), 10(4), or 10(6) cells per egg. Both fresh and inoculated eggs were stored at 4, 10, and 22 degrees C for 6 weeks. Five fresh uninoculated eggs from each storage group were collected each week, and the weight, volume, and pH of the egg albumen were measured. The forces, energies, and degrees of membrane deformation required to rupture the vitelline membranes also were determined from either albumen-free yolks or yolks surrounded by albumen. In separate experiments, five inoculated eggs were evaluated each week for populations of Salmonella Enteritidis. When the eggs were stored at 4 degrees C, the albumen retained significantly more volume and weight and had a relatively lower pH. The vitelline membranes from eggs stored at 4 and 10 degrees C required more force and energy for rupture. Salmonellae flourished at 22 degrees C, even in the albumen with the lowest initial population, 10(2) cells per egg. Storage at 4 and 10 degrees C inhibited the growth of salmonellae in the albumen of eggs with initial populations of 10(2), 10(4), or 10(6) cells per egg. In eggs with initial Salmonella populations of 10(6) cells per egg that were stored at 22 degrees C, the populations of reached as high as 10(10) cells per egg after 4 weeks of storage. Storage at 4 and perhaps 10 degrees C postponed the aging process of chicken eggs, preserved the antimicrobial agents of the albumen, and maintained the integrity of vitelline membrane. Low-temperature storage therefore had a significant impact on the safety and overall quality of the eggs.

Animals↗
PubMed1976

Contributions to an analysis of the avian vitelline membrane's potential to promote outgrowth of the yolk sac-serosal membrane.

Explanted blastoderms of freshly laid chicken eggs expand their area during the first 44-45 hours of incubation by a factor of at least 11 if they are placed with the epiblast on the inner surface of explanted fresh chick vitelline membrane and provided with chick egg extract. This expansion is due essentially to the spreading of the yolk sac-serosal membrane. On turkey and duck membrane the expansion factor is about 6 and 3.8 respectively under otherwise identical conditions, but 1.9 only on a semisolid nutrient agar plate. Only the inner surface of the vitelline membrane has this growth-promoting potential, which markedly and progressively declines during incubation in ovo because of systemic factors rather than because of a direct influence by the outgrowing yolk sac-serosal membrane. Trypsinization of fresh chick vitelline membrane (1% trypsin 3 hours) reduces the growth-promoting potential to about 40% of its normal strength. The outgrowth of the extraembryonic tissues on vitelline membrane is better supported in the presence of a species' own egg extract than by extract from another species.

Animals↗
PubMed1981

[Ecto-mesodermal interactions and chick embryo limb chondrogenesis. Ultrastructural studies of cultures in the vitelline membrane (author's transl)].

Stage 17 (Hamburger and Hamilton) limb mesoderm, isolated and cultured in vitro differentiates into cartilage (11.5% of the explants). However, chondrogenesis is considerably improved in the presence of ectoderm, whether the interacting tissues are in close contact or separated by the vitelline membrane. Stage 15-16 limb mesoderm cultured in vitro is unable to differentiate into cartilage. Previous experiments have shown that a contact between ectoderm and mesoderm is necessary for the induction of cartilage to take place. However, when the vitelline membrane separates the two tissues, cartilage differentiation occurs in 16.3% of the explants. Can a contact between the two interacting tissues be established through the vitelline membrane? Ultrastructural studies of the relationships between ectodermal and mesodermal cells and the vitelline membrane have shown that such a contact can be achieved by means of long mesodermal cell processes penetrating deeply into the vitelline membrane.

Animals↗
PubMed1985

Isolation, characterization and localization of a lectin within the vitelline membrane of the hen's egg.

A lectin with an affinity for certain sulphated polysaccharides, such as fucoidin and dextran sulphate, has been isolated from the vitelline membrane of hens' eggs and purified to homogeneity as assessed by two-dimensional gel electrophoresis. Polyclonal and monoclonal antibodies have been raised to the lectin and used in indirect immunofluorescence microscopy to localize the agglutinin in the outer layer of the vitelline membrane, where the lectin persists prior to the breakdown of the vitelline membrane. The quantity of lectin extracted from the two layers of the membrane, which have been separated by the method of Bellairs, Harkness & Harkness (1963), correlated well with the results of immunofluorescence microscopy. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the two layers of the membrane indicates that each layer has a distinctive polypeptide composition, the outer layer containing in particular lysozyme and avidin. The evidence obtained in this study indicates that the lectin is not involved in adhesion of the blastoderm to the vitelline membrane; neither is it involved in the expression of the blastoderm nor in maintaining the strength of the membrane. The possible roles in promoting transport of solutes across the membrane as well as providing bactericidal properties to the egg are discussed.

Animals↗