海鞘再生的细胞学过程及其调控机制研究进展与展望

Research Progress and Prospect in Cellular Processes and Molecular Mechanisms of Regeneration in Ascidians

再生现象在后生动物中普遍存在,但不同物种的再生能力存在显著差别。无脊椎动物如水螅和涡虫等再生能力较强,具有部分组织或细胞即可再生出一个完整个体的能力,被称为整体再生;而脊椎动物的再生能力相对较弱,局限在某些特定器官或身体结构,被称为部分再生,如蝾螈的附肢。海鞘作为进化上介于无脊椎动物与脊椎动物之间的尾索动物,既包括具备整体再生能力的群居类型,如拟菊海鞘(Botrylloides leachii),其可以利用部分血管残片即可再生出完整个体;也包括只具有部分再生能力的单体海鞘类型,如玻璃海鞘(Ciona robusta),其只有出入水管和神经复合体等器官才可再生。鉴于海鞘的进化地位及其具有的不同再生能力类群,近年来逐渐成为研究再生的理想模式动物。该文系统分析总结了海鞘不同类群所具备的整体再生和部分再生的各自细胞学过程及其调控机制,并比较归纳了导致海鞘不同群体具有不同再生能力差别的可能机制,展望了海鞘再生研究的未来方向,为理解后生动物再生能力的演化和调控机制提供参考。

Regenerative ability broadly but unevenly exists across metazoan phyla.Invertebrates such as the hydra or planarian regenerate the whole body from a piece of tissue or cell population,while only part of limited organs can be regenerated in vertebrates such as the limb of salamander.The ascidian,which is invertebrate chordates and the closest relatives of vertebrates evolutionarily,shows robust but variable regenerative ability among different species.Colonial ascidians such as Botrylloides leachii are capable of completing regeneration of entire new bodies with nothing but small fragments of extracorporeal vasculature,while solitary ascidians such as Ciona robusta can only regenerate distal structures upon injury,such as the siphons and their cerebral ganglion.The ascidian has gradually become an ideal animal model for regeneration study in view of its evolutionary position and coexisting of two kinds of regeneration.This review summarizes the cellular processes and molecular mechanisms of whole-body and partial-body regenerations that have been identified so far in different ascidian species.The difference of mechanisms underlying two kinds of regeneration types is discussed,and the prospect is put forward for future research that hope to be helpful for the understanding of the evolution and regulation of regeneration among metazoans.