Kvach A Yu, Kutyumov V A, Starunov V V, Ostrovsky A N
Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Saint Petersburg, Russia.
Laboratory of Evolutionary Morphology, Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia.
J Exp Zool B Mol Dev Evol. 2025 May;344(3):119-135. doi: 10.1002/jez.b.23285. Epub 2025 Jan 20.
Colonial invertebrates consist of iterative semi-autonomous modules (usually termed zooids) whose lifespan is significantly shorter than that of the entire colony. Typically, module development begins with budding and ends with degeneration. Most studies on the developmental biology of colonial invertebrates have focused on blastogenesis, whereas the changes occurring throughout the entire zooidal life were examined only for a few tunicates. Here we provide the first description of transcriptomic changes during polypide development in the freshwater bryozoan Cristatella mucedo. For the first time for Bryozoa, we performed bulk RNA sequencing of six polypide stages in C. mucedo (buds, juvenile polypides, three mature stages, and degeneration stage) and generated a high-quality de novo reference transcriptome. Based on these data, we analyzed clusters of differentially expressed genes for enriched pathways and biological processes that may be involved in polypide budding, growth, active functioning, and degradation. Although stem cells have never been described in Bryozoa, our analysis revealed the expression of conservative "stemness" markers in developing buds and juvenile polypides. Our data also indicate that polypide degeneration is a complex regulated process involving autophagy and other types of programmed cell death. We hypothesize that the mTOR signaling pathway plays an important role in regulating the polypide lifespan.
群体无脊椎动物由迭代的半自主模块（通常称为个员）组成，其寿命明显短于整个群体。通常，模块发育始于出芽，止于退化。大多数关于群体无脊椎动物发育生物学的研究都集中在芽体发生上，而对于整个个员生命周期中发生的变化，仅对少数被囊动物进行了研究。在这里，我们首次描述了淡水苔藓虫穆氏晶囊轮虫个虫发育过程中的转录组变化。我们首次对穆氏晶囊轮虫的六个个虫阶段（芽体、幼年个虫、三个成熟阶段和退化阶段）进行了大量RNA测序，并生成了高质量的从头参考转录组。基于这些数据，我们分析了差异表达基因簇，以寻找可能参与个虫出芽、生长、活跃功能和降解的富集途径和生物学过程。尽管苔藓虫中从未描述过干细胞，但我们的分析揭示了保守的“干性”标记物在发育中的芽体和幼年个虫中的表达。我们的数据还表明，个虫退化是一个复杂的调控过程，涉及自噬和其他类型的程序性细胞死亡。我们假设mTOR信号通路在调节个虫寿命中起重要作用。
