Synthesis of heterogeneous mRNA-like RNA and low-molecular-weight RNA before the midblastula transition in embryos of Xenopus laevis
It has been proposed and is now widely accepted that in Xenopus laevis embryogenesis RNA synthesis starts only at and after 12 rounds of cleavage, at the time of the midblastula transition (MBT). In this report, however, we provide evidence that RNA synthesis takes place prior to the MBT stage in normally developing Xenopus embryos. In the present experiments, we cultured fertilized eggs in 80 mM phosphate buffer and loosened the adhesion between blastomeres, so that (/sup 3/H)uridine could be incorporated into blastomeres from the surrounding medium. By this method and also by microinjection of (/sup 3/H)GTP, we found that embryos synthesize heterogeneous, nonribosomal, high-molecular-weight RNAs and a relatively small amount of low-molecular-weight RNA as early as the sixth cleavage. RNAs synthesized were not of mitochondrial origin, and the synthesis was sensitive to actinomycin D and alpha-amanitin. From these results we conclude that mRNA-like RNA and low-molecular-weight RNA start to be synthesized during the cleavage stage.
- Research Organization:
- Kyushu Univ., Fukuoka, Japan
- OSTI ID:
- 5630390
- Journal Information:
- Dev. Biol.; (United States), Vol. 123:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FROGS
ONTOGENESIS
RNA
BIOSYNTHESIS
CLEAVAGE
EMBRYOS
MOLECULAR WEIGHT
NUCLEOTIDES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
URIDINE
AMPHIBIANS
ANIMALS
AQUATIC ORGANISMS
AZINES
CRYSTAL STRUCTURE
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MICROSTRUCTURE
NUCLEIC ACIDS
NUCLEOSIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RIBOSIDES
SYNTHESIS
URACILS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques