Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
Little is known about how metabolism changes during development. For most animal embryos, yolk protein is a principal source of nutrition, particularly of essential amino acids. Within eggs, yolk is stored inside large organelles called yolk platelets (YPs). We have gained insight into embryonic nutrition in the African clawed frog Xenopus laevis by studying YPs. Amphibians follow the ancestral pattern in which all embryonic cells inherit YPs from the eggcytoplasm. These YPs are consumed intracellularly at some point during embryogenesis, but it was not known when, where or how yolk consumption occurs. We have identified the novel yolk protein Seryp by biochemical and mass spectrometric analyses of purified YPs. Within individual YPs, Seryp is degraded to completion earlier than the major yolk proteins, thereby providing a molecular marker for YPs engaged in yolk proteolysis. We demonstrate that yolk proteolysis is a quantal process in which a subset of dormant YPs within embryonic cells are reincorporated into the endocytic system and become terminal degradative compartments. Yolk consumption is amongst the earliest aspects of differentiation. The rate of yolk consumption is also highly tissue specific, suggesting that nutrition in early amphibian embryos is tissue autonomous. But yolk consumption does not appear to be triggered by embryonic cells declining to a critically small size. Frog embryos offer a promising platform for the in vivo analysis of metabolism.
Baum,
Coordinate expression of ribosomal protein genes during Xenopus development.
1985, Pubmed,
Xenbase
Baum,
Coordinate expression of ribosomal protein genes during Xenopus development.
1985,
Pubmed
,
Xenbase
Beck,
pNiXa, a Ni(2+)-binding protein in Xenopus oocytes and embryos, shows identity to Ep45, an estrogen-regulated hepatic serpin.
1992,
Pubmed
,
Xenbase
Billett,
Fine structural changes in the differentiating epidermis of Xenopus laevis embryos.
1971,
Pubmed
,
Xenbase
BOELL,
Biochemical differentiation during amphibian development.
1948,
Pubmed
Brooks,
The major yolk protein in sea urchins is a transferrin-like, iron binding protein.
2002,
Pubmed
Chalmers,
The Xenopus tadpole gut: fate maps and morphogenetic movements.
2000,
Pubmed
,
Xenbase
Danilchik,
Differentiation of the animal-vegetal axis in Xenopus laevis oocytes. I. Polarized intracellular translocation of platelets establishes the yolk gradient.
1987,
Pubmed
,
Xenbase
den Elzen,
Cyclin A is destroyed in prometaphase and can delay chromosome alignment and anaphase.
2001,
Pubmed
Dworkin,
Carbon metabolism in early amphibian embryos.
1991,
Pubmed
,
Xenbase
Fagotto,
Regulation of yolk degradation, or how to make sleepy lysosomes.
1995,
Pubmed
Fagotto,
Changes in yolk platelet pH during Xenopus laevis development correlate with yolk utilization. A quantitative confocal microscopy study.
1994,
Pubmed
,
Xenbase
Fischer,
Metabolism of oocyte construction and the generation of histospecificity in the cleaving egg. Lessons from nereid annelids.
1996,
Pubmed
Getz,
Paraoxonase, a cardioprotective enzyme: continuing issues.
2004,
Pubmed
Grant,
Receptor-mediated endocytosis in the Caenorhabditis elegans oocyte.
1999,
Pubmed
Grbac-Ivankovic,
Lipovitellin 2 beta is the 31 kD Ni(2+)-binding protein (pNiXb) in Xenopus oocytes and embryos.
1994,
Pubmed
,
Xenbase
Hagedorn,
Vitellogenin synthesis by the fat body of the mosquito Aedes aegypti: evidence of transcriptional control.
1973,
Pubmed
Hardcastle,
Distinct effects of XBF-1 in regulating the cell cycle inhibitor p27(XIC1) and imparting a neural fate.
2000,
Pubmed
,
Xenbase
Harris,
Neuronal determination without cell division in Xenopus embryos.
1991,
Pubmed
,
Xenbase
Hayakawa,
Precursor structure of egg proteins in the coral Galaxea fascicularis.
2006,
Pubmed
Holland,
A major estrogen-regulated protein secreted from the liver of Xenopus laevis is a member of the serpin superfamily. Nucleotide sequence of cDNA and hormonal induction of mRNA.
1992,
Pubmed
,
Xenbase
Holland,
Estrogen induction of a 45 kDa secreted protein coordinately with vitellogenin in Xenopus liver.
1987,
Pubmed
,
Xenbase
Irving,
Phylogeny of the serpin superfamily: implications of patterns of amino acid conservation for structure and function.
2000,
Pubmed
Jacobsen,
The chicken oocyte receptor for lipoprotein deposition recognizes alpha 2-macroglobulin.
1995,
Pubmed
Jared,
Distribution of incorporated and synthesized protein among cell fractions of Xenopus oocytes.
1973,
Pubmed
,
Xenbase
KARASAKI,
STUDIES ON AMPHIBIAN YOLK. 5. ELECTRON MICROSCOPIC OBSERVATIONS ON THE UTILIZATION OF YOLK PLATELETS DURING EMBRYOGENESIS.
1963,
Pubmed
Kimble,
Tissue-specific synthesis of yolk proteins in Caenorhabditis elegans.
1983,
Pubmed
Komazaki,
Degradation of yolk platelets in the early amphibian embryo is regulated by fusion with late endosomes.
1999,
Pubmed
Komazaki,
Regional differences in yolk platelet degradation activity and in types of yolk platelets degraded during early amphibian embryogenesis.
2002,
Pubmed
Kotyza,
Interactions of serine proteinases with pNiXa, a serpin of Xenopus oocytes and embryos.
1998,
Pubmed
,
Xenbase
Montorzi,
Vitellogenin and lipovitellin: zinc proteins of Xenopus laevis oocytes.
1995,
Pubmed
,
Xenbase
Neff,
Experimental analyses of cytoplasmic rearrangements which follow fertilization and accompany symmetrization of inverted Xenopus eggs.
1984,
Pubmed
,
Xenbase
Newport,
A major developmental transition in early Xenopus embryos: I. characterization and timing of cellular changes at the midblastula stage.
1982,
Pubmed
,
Xenbase
Ohlendorf,
Lipid and polypeptide components of the crystalline yolk system from Xenopus laevis.
1977,
Pubmed
,
Xenbase
Opresko,
Differential postendocytotic compartmentation in Xenopus oocytes is mediated by a specifically bound ligand.
1980,
Pubmed
,
Xenbase
Pierandrei-Amaldi,
Expression of ribosomal-protein genes in Xenopus laevis development.
1982,
Pubmed
,
Xenbase
Richard-Parpaillon,
G1/S phase cyclin-dependent kinase overexpression perturbs early development and delays tissue-specific differentiation in Xenopus.
2004,
Pubmed
,
Xenbase
Romano,
Vertebrate yolk proteins: a review.
2004,
Pubmed
ROTH,
YOLK PROTEIN UPTAKE IN THE OOCYTE OF THE MOSQUITO AEDES AEGYPTI. L.
1964,
Pubmed
Saka,
Spatial and temporal patterns of cell division during early Xenopus embryogenesis.
2001,
Pubmed
,
Xenbase
Schneider,
Vitellogenin receptors: oocyte-specific members of the low-density lipoprotein receptor supergene family.
1996,
Pubmed
Selchow,
Structure and cytoskeletal organization of migratory mesoderm cells from the Xenopus gastrula.
1997,
Pubmed
,
Xenbase
Selman,
The utilization of yolk platelets by tissues of Xenopus embryos studied by a safranin staining method.
1965,
Pubmed
,
Xenbase
Smolenaars,
Molecular diversity and evolution of the large lipid transfer protein superfamily.
2007,
Pubmed
Sunderman,
Characterization of pNiXa, a serpin of Xenopus laevis oocytes and embryos, and its histidine-rich, Ni(II)-binding domain.
1996,
Pubmed
,
Xenbase
Thompson,
Lipid-protein interactions in lipovitellin.
2002,
Pubmed
TUFT,
The uptake and distribution of water in the embryo of Xenopus laevis (Daudin).
1962,
Pubmed
,
Xenbase
Wahli,
Vitellogenesis and the vitellogenin gene family.
1981,
Pubmed
,
Xenbase
WALLACE,
Studies on amphibian yolk. 2. The isolation of yolk platelets from the eggs of Rana pipiens.
1963,
Pubmed
Wiley,
The structure of vitellogenin. Multiple vitellogenins in Xenopus laevis give rise to multiple forms of the yolk proteins.
1981,
Pubmed
,
Xenbase
