Schnitzler Christine E, Song Jingwei, de Jong Danielle
Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Florida 32080, USA.
Department of Biology, University of Florida, Gainesville, Florida 32611, USA.
Integr Comp Biol. 2025 Jun 12. doi: 10.1093/icb/icaf090.
For over a century, the colonial cnidarian Hydractinia has been employed as a research organism to study stem cells, germ cells, regeneration, and coloniality. For the last 70 years, it has also been used in allorecognition research within the field of comparative immunology. More recently, other aspects of Hydractinia biology, including sensory biology, have been explored. Hydractinia colonies are composed of a limited number of repeating structural units: polyps and the stolon tissue that connects polyps. Polyps are divided into three major types used for feeding, reproduction, or defense. Clonal lines grown in the lab provide unlimited material from a single genetic unit. Colonies have separate sexes and spawn regularly with exposure to light. Recently, genomic and transcriptomic resources have been released for two species of Hydractinia: H. symbiolongicarpus and H. echinata. Tools for gene expression manipulation have been developed for this organism including CRISPR/Cas9 knockout, shRNA knockdown, and overexpression via synthetic RNA. Fluorescent transgenic reporter lines have been created via random integration of circular DNA plasmids and CRISPR/Cas9-mediated gene knockin. We recently constructed an updated single-cell transcriptomic atlas of adult Hydractinia colonies to explore the cellular biology and cell-type expression profiles of the animal. We are investigating known and novel cell types and validating spatial expression patterns of cell-type specific markers to enable further understanding of the animal's cellular biology. This includes gaining a deeper understanding of the genetic control of cell differentiation of specific cell types from progenitor populations and uncovering the diversity of transcriptional subtypes that may be relevant to specific functions. Since Hydractinia is a model for whole-body regeneration, the identification and validation of new cell type and cell state markers will now allow for the elucidation of potential pathways involved in regenerating specific cell types, including testing alternative pathways for regeneration that include dedifferentiation and transdifferentiation. Hydractinia is poised to become a model for sensory biology research as we can now fully explore their sensory cell types, including cnidocytes and neurons, and the expression and evolution of their gene complement with modern approaches and tools.
一个多世纪以来，群居刺胞动物水螅虫一直被用作研究干细胞、生殖细胞、再生和群居性的研究生物。在过去的70年里，它也被用于比较免疫学领域的同种异体识别研究。最近，水螅虫生物学的其他方面，包括感觉生物学，也得到了探索。水螅虫群体由数量有限的重复结构单元组成：水螅体和连接水螅体的匍匐茎组织。水螅体分为用于摄食、繁殖或防御的三种主要类型。在实验室中培养的克隆系提供了来自单个遗传单位的无限材料。群体有不同的性别，在光照下会定期产卵。最近，已经公布了两种水螅虫的基因组和转录组资源：共生长柄水螅虫和刺状水螅虫。已经为这种生物开发了基因表达操纵工具，包括CRISPR/Cas9基因敲除、shRNA干扰和通过合成RNA进行过表达。通过环状DNA质粒的随机整合和CRISPR/Cas9介导的基因敲入，创建了荧光转基因报告系。我们最近构建了一个更新的成年水螅虫群体单细胞转录组图谱，以探索该动物的细胞生物学和细胞类型表达谱。我们正在研究已知和新的细胞类型，并验证细胞类型特异性标记的空间表达模式，以进一步了解该动物的细胞生物学。这包括更深入地了解特定细胞类型从祖细胞群体分化的遗传控制，并揭示可能与特定功能相关的转录亚型的多样性。由于水螅虫是全身再生的模型，新细胞类型和细胞状态标记的识别和验证现在将有助于阐明参与再生特定细胞类型的潜在途径，包括测试包括去分化和转分化在内的替代再生途径。水螅虫有望成为感觉生物学研究的模型，因为我们现在可以用现代方法和工具充分探索它们的感觉细胞类型，包括刺细胞和神经元，以及它们基因互补的表达和进化。
