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The initiation of new gene transcription during Xenopus gastrulation requires immediately preceding protein synthesis
1Department of Zoology, University of Cambridge, UK.
Abstract:
The incubation of Xenopus embryo fragments in cycloheximide at 5 or 10 micrograms ml-1 rapidly inhibits protein synthesis to 10% or less of control levels. In most batches of embryos, treatment with cycloheximide for up to 1 h causes no obvious cellular damage and protein synthesis is fully restored to normal levels 5 h later. Transcript analysis with RNA probes shows that the inhibition of protein synthesis at late blastula or early gastrula stages completely suppresses the normal initiation of actin gene transcription at the mid-late gastrula stage. This applies to muscle-specific actin genes, whose transcription is initiated by induction, as well as to cytoskeletal actin genes not activated by induction. Two-dimensional gel protein analysis shows that cycloheximide irreversibly inhibits only 10% of all genes normally expressed at a postneurula stage and that all of these are genes whose expression is normally initiated during or soon after gastrulation. Cycloheximide treatment causes a limited reduction of DNA synthesis, and no reduction of overall RNA synthesis. We conclude that the initiation of new gene transcription during gastrulation in Xenopus is dependent on the immediately preceding synthesis of certain proteins.
Insights
Cycloheximide treatment inhibits protein synthesis in Xenopus embryos, blocking new gene transcription during gastrulation. This suggests that protein synthesis is essential for initiating gene expression in early development.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Protein synthesis is crucial for cellular function and development.
- Gene transcription regulation is a key process in embryonic development.
Purpose of the Study:
- To investigate the role of protein synthesis in initiating gene transcription during Xenopus gastrulation.
- To determine if new protein synthesis is required for the activation of specific genes during embryonic development.
Main Methods:
- Xenopus embryo fragments were incubated with cycloheximide to inhibit protein synthesis.
- Transcript analysis using RNA probes was performed to assess gene transcription.
- Two-dimensional gel electrophoresis was used for protein analysis.
Main Results:
- Cycloheximide rapidly inhibited protein synthesis to low levels without causing significant cellular damage.
- Inhibition of protein synthesis suppressed the initiation of actin gene transcription.
- Only a small percentage of genes normally expressed later were affected, and these were initiated during gastrulation.
Conclusions:
- Initiation of new gene transcription during Xenopus gastrulation is dependent on preceding protein synthesis.
- Specific proteins synthesized during gastrulation are required for the activation of subsequent gene expression.
- This highlights a critical link between protein synthesis and transcriptional regulation in early development.