Microinjection methods for sea urchin eggs and blastomeres

Methods for microinjection into sea urchin eggs have become relatively easier because of the technical improvements by a number of researchers in the past decades. However, the size and the characteristics, such as the elasticity and toughness, of the eggs and embryos differ in species, so that we still need to modify the details of methods to adapt to each target. In this section, I list microinjection methods for three species: Hemicentrotus pulcherrimus, which has relatively tough eggs, Temnopleurus reevesii, which has slightly weak eggs, and Strongylocentrotus purpuratus, which is the most used species in sea urchin biology. In addition, I describe the methods for co-injection of morpholino anti-sense oligonucleotides and mRNAs, as well as the method for microinjection into blastomeres.

Temnopleurus as an emerging echinoderm model

Sea urchins have played important roles in cell and developmental biology. They have the potential to be even more useful as models if the ability to create transgenic animals and maintain genetic lines are developed. Here, I describe the methods to produce next-generation lines using a newly introduced sea urchin model, Temnopleurus reevesii, in the laboratory. The embryos of T. reevesii have wide range of temperature tolerance between 15°C to 30°C and have high transparency, which can be a strong point in live-imaging and fluorescent immunohistochemistry. I describe how to grow and culture the embryos/larvae/juveniles/adults of T. reevesii to address the challenge of establishing inbred strains followed by introducing genetics into this species in the future.