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Histone synthesis by cleavage arrested sea urchin eggs
Cell Differentiation
|June 1, 1978
Summary
Histone synthesis shifts from Hlm to Hlg in early embryos, even without cell division. This change is driven by newly transcribed DNA, indicating a programmed developmental switch.
Area of Science:
- Developmental Biology
- Molecular Biology
- Genetics
Background:
- Histone synthesis undergoes significant changes during early embryonic development.
- Specific histone variants, Hlm and Hlg, are observed to change during blastula stages.
Purpose of the Study:
- To investigate the timing and regulation of histone Hlm and Hlg synthesis.
- To determine if histone synthesis shifts occur independently of normal embryonic cleavage.
- To identify the genetic origin of Hlm and Hlg synthesis in hybrid embryos.
Main Methods:
- Acrylamide gel electrophoresis to differentiate histone variants.
- Labeling embryos with L-[3H]lysine to track protein synthesis.
- Utilizing hybrid and homospermic embryos.
- Inhibiting embryonic cleavage by culturing at 11°C.
Main Results:
- Histone Hlm and Hlg are synthesized sequentially in both normal and cleavage-inhibited embryos.
- Hybrid embryo data indicate Hlm is translated from newly transcribed paternal mRNA.
- Hlg synthesis occurs in both hybrid and homospermic embryos during later development.
Conclusions:
- The shift in histone synthesis (Hlm to Hlg) is a programmed event independent of cleavage.
- Histone Hlm synthesis relies on transcription from paternal DNA.
- Histone Hlg synthesis is regulated independently and occurs later in development.