Studying the generation of biomechanical force and how this force drives cell and tissue morphogenesis is challenging for understanding the mechanical mechanisms underlying embryogenesis. Actomyosin has been demonstrated to be the main source of intracellular force generation that drives membrane and cell contractility, thus playing a vital role in multi-organ formation in ascidian Ciona embryogenesis. However, manipulation of actomyosin at the subcellular level is impossible in Ciona because of the lack of technical tools and approaches. In this study, we designed and developed a myosin light chain phosphatase fused with a light-oxygen-voltage flavoprotein from Botrytis cinerea (MLCP-BcLOV4) as an optogenetics tool to control actomyosin contractility activity in the Ciona larva epidermis. We first validated the light-dependent membrane localization and regulatory efficiency on mechanical forces of the MLCP-BcLOV4 system as well as the optimum light intensity that activated the system in HeLa cells. Then, we applied the optimized MLCP-BcLOV4 system in Ciona larval epidermal cells to realize the regulation of membrane elongation at the subcellular level. Moreover, we successfully applied this system on the process of apical contraction during atrial siphon invagination in Ciona larvae. Our results showed that the activity of phosphorylated myosin on the apical surface of atrial siphon primordium cells was suppressed and apical contractility was disrupted, resulting in the failure of the invagination process. Thus, we established an effective technique and system that provide a powerful approach in the study of the biomechanical mechanisms driving morphogenesis in marine organisms.

Evolutionary developmental biology (evo-devo) has been among the most fascinating interdisciplinary fields for decades, which aims to elucidate the origin and evolution of diverse developmental processes. The rapid accumulation of omics data provides unprecedented opportunities to answer many interesting but unresolved evo-devo questions. However, the access and utilization of these resources are hindered by challenges particularly in non-model animals. Here, we establish a comparative multi-omics database for animal evo-devo (EDomics, http://edomics.qnlm.ac) containing comprehensive genomes, bulk transcriptomes, and single-cell data across 40 representative species, many of which are generally used as model organisms for animal evo-devo study. EDomics provides a systematic view of genomic/transcriptomic information from various aspects, including genome assembly statistics, gene features and families, transcription factors, transposable elements, and gene expressional profiles/networks. It also exhibits spatiotemporal gene expression profiles at a single-cell level, such as cell atlas, cell markers, and spatial-map information. Moreover, EDomics provides highly valuable, customized datasets/resources for evo-devo research, including gene family expansion/contraction, inferred core gene repertoires, macrosynteny analysis for karyotype evolution, and cell type evolution analysis. EDomics presents a comprehensive and comparative multi-omics platform for animal evo-devo community to decipher the whole history of developmental evolution across the tree of life.