Vimentin expression in oocytes, eggs and early embryos of Xenopus laevis

Immunocytochemical studies using a monoclonal anti-porcine vimentin antibody reveal a well-organized pattern of staining in Xenopus laevis oocytes, eggs and early embryos. The positions of Xenopus vimentin and desmin in two-dimensional (2D) polyacrylamide gels were first established by immunoblotting of muscle Triton extracts with anti-intermediate filament antibodies (anti-IFA), which cross-react with all intermediate filament proteins (IFPs). The anti-porcine vimentin reacts with vimentin and desmin in muscle 2D immunoblots, but only reacts with one polypeptide in oocyte blots in the position predicted for vimentin (Mr 55 × 10(3), pI 5.6). Using an anti-sense probe derived from a Xenopus vimentin genomic clone in RNase protection assays, we show that expression of vimentin begins in previtellogenic oocytes. The level of expression remains constant throughout oogenesis and in unfertilized eggs. These data suggest that vimentin is expressed in oocytes and eggs. Most interestingly, the immunocytochemical results also show that vimentin is present in the germ plasma of oocytes, eggs and early embryos. It is therefore possible that vimentin has an important role in the formation or behaviour of early germ line cells.

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Performing Functional Studies of Xenopus laevis Intermediate Filament Proteins Through Injection of Macromolecules into Early Embryos

Intermediate Filament Cytoskeleton - Methods in Cell Biology ◽

10.1016/s0091-679x(04)78023-1 ◽

2004 ◽

pp. 673-701 ◽

Cited By ~ 5

Author(s):

Christine Gervasi ◽

Ben G. Szaro

Keyword(s):

Xenopus Laevis ◽

Intermediate Filament ◽

Intermediate Filament Proteins ◽

Functional Studies ◽

Early Embryos

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Expression of intermediate filament proteins during development of Xenopus laevis. I. cDNA clones encoding different forms of vimentin

Development ◽

10.1242/dev.105.2.279 ◽

1989 ◽

Vol 105 (2) ◽

pp. 279-298

Author(s):

H. Herrmann ◽

B. Fouquet ◽

W.W. Franke

Keyword(s):

Amino Acid ◽

Xenopus Laevis ◽

Intermediate Filament ◽

De Novo ◽

Mesenchymal Cell ◽

Amino Acid Sequences ◽

Cytoskeletal Proteins ◽

Cdna Clones ◽

Mammalian Development ◽

Intermediate Filament Proteins

To provide a basis for studies of the expression of genes encoding the diverse kinds of intermediate-filament (IF) proteins during embryogenesis of Xenopus laevis we have isolated and characterized IF protein cDNA clones. Here we report the identification of two types of Xenopus vimentin, Vim1 and Vim4, with their complete amino acid sequences as deduced from the cloned cDNAs, both of which are expressed during early embryogenesis. In addition, we have obtained two further vimentin cDNAs (Vim2 and 3) which are sequence variants of closely related Vim1. The high evolutionary conservation of the amino acid sequences (Vim1: 458 residues; Mr approximately 52,800; Vim4: 463 residues; Mr approximately 53,500) to avian and mammalian vimentin and, to a lesser degree, to desmin from the same and higher vertebrate species, is emphasized, including conserved oligopeptide motifs in their head domains. Using these cDNAs in RNA blot and ribonuclease protection assays of various embryonic stages, we observed a dramatic increase of vimentin RNA at stage 14, in agreement with immunocytochemical results obtained with antibody VIM-3B4. The significance of very weak mRNA signals detected in earlier stages is discussed in relation to negative immunocytochemical results obtained in these stages. The first appearance of vimentin has been localized to a distinct mesenchymal cell layer underlying the neural plate or tube, respectively. The results are discussed in relation to programs of de novo synthesis of other cytoskeletal proteins in amphibian and mammalian development.

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Developmentally regulated cytokeratin gene in Xenopus laevis.

Molecular and Cellular Biology ◽

10.1128/mcb.5.10.2575 ◽

1985 ◽

Vol 5 (10) ◽

pp. 2575-2581 ◽

Cited By ~ 37

Author(s):

J A Winkles ◽

T D Sargent ◽

D A Parry ◽

E Jonas ◽

I B Dawid

Keyword(s):

Amino Acid ◽

Xenopus Laevis ◽

Intermediate Filament ◽

Type I ◽

Developmentally Regulated ◽

Amino Acid Homology ◽

Intermediate Filament Proteins ◽

Functional Roles ◽

Terminal Domain ◽

Terminal Domains

We have determined the sequence of cloned cDNAs derived from a 1,665-nucleotide mRNA which transiently accumulates during Xenopus laevis embryogenesis. Computer analysis of the deduced amino acid sequence revealed that this mRNA encodes a 47-kilodalton type I intermediate filament subunit, i.e., a cytokeratin. As is common to all intermediate filament subunits so far examined, the predicted polypeptide, named XK70, contains N- and C-terminal domains flanking a central alpha-helical rod domain. The overall amino acid homology between XK70 and a human 50-kilodalton type I keratin is 47%; homology within the alpha-helical domain is 57%. The N-terminal domain, which is not completely contained in our cDNAs, is basic, contains 42% serine plus alanine, and includes five copies of a six-amino-acid repeating unit. The C-terminal domain has a high alpha-helical content and contains a region with sequence homology to the C-terminal domains of other type I and type III intermediate filament proteins. We suggest that different keratin filament subtypes may have different functional roles during amphibian oogenesis and embryogenesis.

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Immunocytochemical identification of non-neuronal intermediate filament proteins in the developing Xenopus laevis nervous system

Developmental Brain Research ◽

10.1016/0165-3806(88)90100-9 ◽

1988 ◽

Vol 43 (2) ◽

pp. 207-224 ◽

Cited By ~ 47

Author(s):

Ben G. Szaro ◽

Harold Gainer

Keyword(s):

Nervous System ◽

Xenopus Laevis ◽

Intermediate Filament ◽

Intermediate Filament Proteins ◽

Neuronal Intermediate Filament Proteins

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Polar asymmetry in the organization of the cortical cytokeratin system of Xenopus laevis oocytes and embryos

Development ◽

10.1242/dev.100.3.543 ◽

1987 ◽

Vol 100 (3) ◽

pp. 543-557 ◽

Cited By ~ 1

Author(s):

M.W. Klymkowsky ◽

L.A. Maynell ◽

A.G. Polson

Keyword(s):

Xenopus Laevis ◽

Mature Stage ◽

Xenopus Laevis Oocytes ◽

Blastula Stage ◽

Early Embryos ◽

Large Fibre ◽

Filament Bundles ◽

Punctate Pattern ◽

Cortical Cytoskeleton ◽

Cytokeratin Filaments

We have used whole-mount immunofluorescence microscopy of late-stage Xenopus laevis oocytes and early embryos to examine the organization of their cortical cytokeratin systems. In both mature oocytes and early embryos, there is a distinct animal-vegetal polarity in cytokeratin organization. In mature (stage-VI) oocytes, the cytokeratin filaments of the vegetal region form a unique, almost geodesic network; in the animal region, cytokeratin organization appears much more variable and irregular. In unfertilized, postgerminal vesicle breakdown eggs, the cortical cytokeratin system is disorganized throughout both animal and vegetal hemispheres. After fertilization, cytokeratin organization reappears first in a punctate pattern that is transformed into an array of oriented filaments. These cytokeratin filaments appear first in the vegetal hemisphere and are initially thin. Subsequently, they form bundles that grow thicker through the period of first to second cleavage, at which point large cytokeratin filament bundles form a loose, fishnet-like system that encompasses the vegetal portion of each blastomere. In the animal region, cytokeratin filaments do not appear to form large fibre networks, but rather appear to be organized into a system of fine filaments. The animal-vegetal polarity in cytokeratin organization persists until early blastula (stage 5); in later-stage embryos, both animal and vegetal blastomeres possess qualitatively similar cytokeratin filament systems. The entire process of cytokeratin reorganization in the egg is initiated by prick activation. These observations indicate that the cortical cytoskeleton of Xenopus oocytes and early embryos is both dynamic and asymmetric.

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