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???
We have measured the expression of 41 maternal mRNAs in individual blastomeres collected from the 8 to 32-cell Xenopus laevis embryos to determine when and how asymmetry in the body plan is introduced. We demonstrate that the asymmetry along the animal-vegetal axis in the oocyte is transferred to the daughter cells during early cell divisions. All studied mRNAs are distributed evenly among the set of animal as well as vegetal blastomeres. We find no asymmetry in mRNA levels that might be ascribed to the dorso-ventral specification or the left-right axis formation. We hypothesize that while the animal-vegetal asymmetry is a consequence of mRNA gradients, the dorso-ventral and left-right axes specifications are induced by asymmetric distribution of other biomolecules, probably proteins.
Figure 1. PCA of profiled blastomeres collected from early developmental stages of Xenopus laevis.Triangles indicate blastomeres from the 8-cell stage; squares from the 16-cell stage, and circles from the 32-cell stage. Blastomeres originating from the animal hemisphere are shown in red and those from the vegetal hemisphere are shown in blue. Left and right graphs are data from two different females (left: four embryos from 8-cell stage, four embryos from 16-cell stage, and one 32-cell stage embryo, in total 128 blastomeres; right: two embryos from 8-cell stage, three from 16-cell stage, and one from 32-cell stage, in total 96 blastomeres).
Figure 2. Hierarchical clustering of blastomeres and mRNAs of Xenopus laevis early embryos presented as heatmaps.One embryo from each developmental stage was arbitrarily chosen for the cluster analysis. (A) 8-cell, (B) 16-cell and (C) 32-cell embryo. Green color indicates low expression and red high expression. The dendrograms clustering blastomeres and genes are shown in the top and left side of the heatmap, respectively. In the dendrograms similarity between blastomeres/genes is indicated by the height at which they are joined.
Figure 3. Principal component analysis of maternal genes.(A) 8-cell stage (four embryos/32 cells analyzed), (B) 16-cell stage (four embryos/64 cells analyzed), and (C) 32-cell stage (32 cells analyzed) embryos. Three clusters are seen in all the developmental stages. First cluster comprises 18S rRNA, 5S rRNA, and cyc1(mitochondrial cytochrome c); second cluster vg1, cdx1 (xcad2), wnt11, dazl, vegt, ddx25 (deadsouth), otx1, and trim36; third cluster (red squares) fzd7, par1, bmp2, pias1, dvl2, dvl3, lrp6, foxr1, fart1, mapk8, odc1, axin1, est1, U3 snoRNA, apc, gapdh, acta, eef1a1, tcf3, zpc, RNA polymerase II, gsk3b, maml1, tubb, ctnnb1 (β-catenin), mos, oct60, foxh1, stat3, and pax6. The animal-vegetal distinction is found along the y-axis (PC2), while differences in expression level of the maternal transcripts is reflected along the x-axis (PC1).
Aanstad,
Predictability of dorso-ventral asymmetry in the cleavage stage zebrafish embryo: an analysis using lithium sensitivity as a dorso-ventral marker.
1999, Pubmed
Aanstad,
Predictability of dorso-ventral asymmetry in the cleavage stage zebrafish embryo: an analysis using lithium sensitivity as a dorso-ventral marker.
1999,
Pubmed Bengtsson,
Gene expression profiling in single cells from the pancreatic islets of Langerhans reveals lognormal distribution of mRNA levels.
2005,
Pubmed Bergkvist,
Gene expression profiling--Clusters of possibilities.
2010,
Pubmed
,
Xenbase Cuykendall,
Vegetally localized Xenopus trim36 regulates cortical rotation and dorsal axis formation.
2009,
Pubmed
,
Xenbase Cuykendall,
Identification of germ plasm-associated transcripts by microarray analysis of Xenopus vegetal cortex RNA.
2010,
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 Darras,
Animal and vegetal pole cells of early Xenopus embryos respond differently to maternal dorsal determinants: implications for the patterning of the organiser.
1997,
Pubmed
,
Xenbase Denegre,
Deep cytoplasmic rearrangements in axis-respecified Xenopus embryos.
1993,
Pubmed
,
Xenbase Galán,
Functional genomics of 5- to 8-cell stage human embryos by blastomere single-cell cDNA analysis.
2010,
Pubmed Guo,
Resolution of cell fate decisions revealed by single-cell gene expression analysis from zygote to blastocyst.
2010,
Pubmed Hainski,
Xenopus maternal RNAs from a dorsal animal blastomere induce a secondary axis in host embryos.
1992,
Pubmed
,
Xenbase Hyatt,
Initiation of vertebrate left-right axis formation by maternal Vg1.
1996,
Pubmed
,
Xenbase Keller,
Vital dye mapping of the gastrula and neurula of Xenopus laevis. II. Prospective areas and morphogenetic movements of the deep layer.
1976,
Pubmed
,
Xenbase Keller,
Vital dye mapping of the gastrula and neurula of Xenopus laevis. I. Prospective areas and morphogenetic movements of the superficial layer.
1975,
Pubmed
,
Xenbase Kikkawa,
Location and behavior of dorsal determinants during first cell cycle in Xenopus eggs.
1996,
Pubmed
,
Xenbase King,
Putting RNAs in the right place at the right time: RNA localization in the frog oocyte.
2005,
Pubmed
,
Xenbase Kofron,
New roles for FoxH1 in patterning the early embryo.
2004,
Pubmed
,
Xenbase Kofron,
Wnt11/beta-catenin signaling in both oocytes and early embryos acts through LRP6-mediated regulation of axin.
2007,
Pubmed
,
Xenbase Kugler,
Localization, anchoring and translational control of oskar, gurken, bicoid and nanos mRNA during Drosophila oogenesis.
2009,
Pubmed Marikawa,
Dorsal determinants in the Xenopus egg are firmly associated with the vegetal cortex and behave like activators of the Wnt pathway.
1997,
Pubmed
,
Xenbase May,
Multiplex rt-PCR expression analysis of developmentally important genes in individual mouse preimplantation embryos and blastomeres.
2009,
Pubmed Medina,
Cortical rotation is required for the correct spatial expression of nr3, sia and gsc in Xenopus embryos.
1997,
Pubmed
,
Xenbase Miller,
Establishment of the dorsal-ventral axis in Xenopus embryos coincides with the dorsal enrichment of dishevelled that is dependent on cortical rotation.
1999,
Pubmed
,
Xenbase Roth,
The origin of dorsoventral polarity in Drosophila.
2003,
Pubmed Schroeder,
Spatially regulated translation in embryos: asymmetric expression of maternal Wnt-11 along the dorsal-ventral axis in Xenopus.
1999,
Pubmed
,
Xenbase Sindelka,
Intracellular expression profiles measured by real-time PCR tomography in the Xenopus laevis oocyte.
2008,
Pubmed
,
Xenbase Sindelka,
Spatial expression profiles in the Xenopus laevis oocytes measured with qPCR tomography.
2010,
Pubmed
,
Xenbase Ståhlberg,
RT-qPCR work-flow for single-cell data analysis.
2013,
Pubmed Steinhauer,
Microtubule polarity and axis formation in the Drosophila oocyte.
2006,
Pubmed Tao,
Maternal wnt11 activates the canonical wnt signaling pathway required for axis formation in Xenopus embryos.
2005,
Pubmed
,
Xenbase Vincent,
Subcortical rotation in Xenopus eggs: an early step in embryonic axis specification.
1987,
Pubmed
,
Xenbase Virant-Klun,
Expression of pluripotency and oocyte-related genes in single putative stem cells from human adult ovarian surface epithelium cultured in vitro in the presence of follicular fluid.
2013,
Pubmed Weaver,
Move it or lose it: axis specification in Xenopus.
2004,
Pubmed
,
Xenbase
