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Updated: Jul 27, 2025
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High Throughput Microinjections of Sea Urchin Zygotes
Published on: January 21, 2014
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THE ORIGIN OF ECHINOID HATCHING ENZYME MESSENGER RNA
Richard M Showman1, Arthur H Whiteley1
1Department of Zoology, University of Washington, Seattle, Washington 98195, USA.
Development, Growth & Differentiation
|June 7, 2023
Summary
Sea urchin and sand dollar hybrid embryos require new mRNA synthesis for hatching. This indicates that the hatching enzyme is not maternally stored but transcribed from embryonic genes.
Area of Science:
- Developmental Biology
- Molecular Biology
- Marine Biology
Background:
- Echinoid embryos utilize a hatching enzyme for development.
- The origin of hatching enzyme messenger RNA (mRNA) in sea urchins is debated: whether it is newly synthesized or maternally provided.
Purpose of the Study:
- To investigate whether echinoid hatching enzyme mRNA is transcribed from embryonic chromatin or stored as maternal mRNA in the unfertilized egg.
Main Methods:
- Construction of hybrid andromerogones using a sea urchin (Strongylocentrotus purpuratus) genome and sand dollar (Dendraster excentricus) cytoplasm.
- Observation of development and hatching success in these hybrid andromerogones.
- Comparison with diploid hybrids and merogones containing a sand dollar genome.
Main Results:
- Hybrid andromerogones developed normally to the blastula stage but failed to hatch.
- Diploid hybrids and merogones with a sand dollar genome component hatched on schedule.
- The sea urchin hatching enzyme could not digest the sand dollar fertilization membrane.
Conclusions:
- New mRNA synthesis from embryonic chromatin is essential for hatching enzyme production.
- Hatching enzyme mRNA is not a maternally stored component in these echinoid species.
- Embryonic gene expression is critical for the synthesis of developmental enzymes like hatching enzyme.
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