A single cell RNA sequencing resource for early sea urchin development

Area of Science:

• Developmental Biology
• Genomics
• Marine Biology

Background:

• Understanding gene regulatory networks is crucial for deciphering developmental processes.
• The sea urchin embryo offers a well-established model for studying early development and gene regulation.

Purpose of the Study:

• To comprehensively map cell states in the *Strongylocentrotus purpuratus* embryo using single-cell RNA sequencing.
• To identify key transition stages and cell types involved in germ layer specification.
• To characterize the transcriptomic profiles of germ cell precursors.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) was performed on eight developmental stages of *Strongylocentrotus purpuratus* embryos.
• Bioinformatic analyses were used to cluster cells and identify distinct cell states.
• Transcriptional profiles were analyzed to identify genes associated with specific cell types, including germ cell factors.

Main Results:

• Identification of 22 major embryonic cell states and over 50 sub-clustered cell states with distinct transcriptomic profiles.
• Characterization of two cell states expressing germ cell factors, one identified as primordial germ cells.
• Observation of a transient cell state during gastrulation expressing germ cell factors, potentially representing a germline precursor lineage.

Conclusions:

• This study provides a high-resolution transcriptomic atlas of the sea urchin embryo, detailing numerous cell states during development.
• The findings offer insights into germ cell specification and identify a potential alternative germline precursor lineage.
• This resource facilitates future research into developmental mechanisms and gene regulatory networks in marine invertebrates.