Abstract BackgroundSea urchin embryos have been used for more than a century in the study of fertilization and early development. However, several of the species used, such asStrongylocentrotus purpuratus, have long generation times making them suboptimal for transgenerational studies. ResultsHere, we present an overview of the development of a rapidly developing echinoderm species,Lytechinus pictus, from fertilization through sexual maturation. When grown at room temperature (20°C) embryos complete the first cell cycle in 90 minutes, followed by subsequent cleavages every 45 minutes, leading to hatching at 9 hours postfertilization (hpf). The swimming embryos gastrulate from 12 to 36 hpf and produce the cells which subsequently give rise to the larval skeleton and immunocytes. Larvae begin to feed at 2 days and metamorphose by 3 weeks. Juveniles reach sexual maturity at 4 to 6 months of age, depending on individual growth rate. ConclusionsThis staging scheme lays a foundation for future studies inL. pictus, which share many of the attractive features of other urchins but have the key advantage of rapid development to sexual maturation. This is significant for multigenerational and genetic studies newly enabled by CRISPR‐CAS mediated gene editing.
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Generation of a homozygous mutant drug transporter (ABCB1) knockout line in the sea urchin Lytechinus pictus
ABSTRACT Sea urchins are premier model organisms for the study of early development. However, the lengthy generation times of commonly used species have precluded application of stable genetic approaches. Here, we use the painted sea urchin Lytechinus pictus to address this limitation and to generate a homozygous mutant sea urchin line. L. pictus has one of the shortest generation times of any currently used sea urchin. We leveraged this advantage to generate a knockout mutant of the sea urchin homolog of the drug transporter ABCB1, a major player in xenobiotic disposition for all animals. Using CRISPR/Cas9, we generated large fragment deletions of ABCB1 and used these readily detected deletions to rapidly genotype and breed mutant animals to homozygosity in the F2 generation. The knockout larvae are produced according to expected Mendelian distribution, exhibit reduced xenobiotic efflux activity and can be grown to maturity. This study represents a major step towards more sophisticated genetic manipulation of the sea urchin and the establishment of reproducible sea urchin animal resources.
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- PAR ID:
- 10334271
- Date Published:
- Journal Name:
- Development
- Volume:
- 149
- Issue:
- 11
- ISSN:
- 0950-1991
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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