Toxic effects of SiO2NPs in early embryogenesis of Xenopus laevis

This article considers some aspects of the storage of macromolecules in the oocyte of Xenopus laevis and the activation of previously unexpressed genes during early embryogenesis. The large quantity and complex nature of poly(A)+ RNA accumulated in the egg provides the cleavage embryo with a supply of mRNA sufficient to sustain protein synthesis for several hours of development. Onset of gene activity at the midblastula transition (MBT) leads to the synthesis and accumulation of molecules of various RNA classes, including tRNAs, rRNAs, mRNAs and mitochondrial RNAs. At gastrulation the poly(A)+ RNA population is still qualitatively similar to that of the egg but some sequences not present in egg RNA have accumulated by this time. Through the use of a subtractive cDNA cloning procedure we have prepared a library of sequences that represent genes activated for the first time between MBT and gastrula. A study of several of these cDNA clones suggests that genes in this class are restricted in their activity to embryonic and tadpole stages.

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Retinal growth in double dorsal and double ventral eyes in Xenopus

Development ◽

10.1242/dev.40.1.175 ◽

1977 ◽

Vol 40 (1) ◽

pp. 175-185

Author(s):

K. Straznicky ◽

D. Tay

Keyword(s):

Xenopus Laevis ◽

Compound Eye ◽

Ganglion Cells ◽

Cell Number ◽

Early Embryogenesis ◽

Time Points ◽

Retinal Growth

The growth of normal and surgically produced compound dorsal and ventral retinae in Xenopus laevis has been studied autoradiographically following injections of [3H]thymidine at stages 50 and 58. The animals were sacrificed 3 weeks after metamorphosis. The histogenetic pattern of the dorsal and ventral retinal halves was different at the three time points investigated, i.e. up to stage 50, between stages 50 and 58 and between stage 58 and 3 weeks after metamorphosis. Asymmetrical dorsal retinal growth occurred up to stage 50. From stage 50 onwards the retinal growth tendency reversed so that more ganglion cells were produced along the ventral than the dorsal ciliary margins. The overall preponderance of ventral retinal growth was 32·4% in cell number and 12·4% in retinal length from early embryogenesis to 3 weeks after metamorphosis. The characteristic histogenetic pattern of the dorsal and ventral retinal halves was maintained in an ectopic position in the compound eye, indicating that this particular property of the retinal halves is intrinsically determined.

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Dynamic distribution of region-specific maternal protein during oogenesis and early embryogenesis of Xenopus laevis

Roux s Archives of Developmental Biology ◽

10.1007/bf00361340 ◽

1991 ◽

Vol 200 (4) ◽

pp. 213-222 ◽

Cited By ~ 9

Author(s):

Akio S. Suzuki ◽

Junichi Manabe ◽

Asako Hirakawa

Keyword(s):

Xenopus Laevis ◽

Early Embryogenesis ◽

Dynamic Distribution

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Region-specific regulation of the actin multi-gene family in early amphibian embryos

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1984.0136 ◽

1984 ◽

Vol 307 (1132) ◽

pp. 337-342 ◽

Cited By ~ 3

Keyword(s):

Molecular Marker ◽

Xenopus Laevis ◽

Gene Family ◽

Early Embryogenesis ◽

Embryonic Tissue ◽

Actin Genes ◽

Amphibian Embryos ◽

Specific Regulation ◽

Somitic Mesoderm

The actin multi-gene family shows both spatial and tem poral regulation during early embryogenesis in the am phibian Xenopus laevis . Both muscle-specific and ubiquitous cytoskeletal actin genes are activated at the end of gastrulation; transcription of the α-cardiac and α-skeletal actin genes is restricted to the somitic mesoderm and its muscle-forming derivatives providing a convenient molecular marker for this early embryonic tissue.

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