Identification of a HSP40 gene involved in planarian regeneration

Ma, Ke; Zhang, He-Cai; Zhang, Yumei; Song, Gege; Wu, Meng; Chen, Guangwen

doi:10.1515/biolog-2017-0157

Cited by 4 publications

(2 citation statements)

References 37 publications

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“…The siRNA studies showed that the major tissues and organs replaced after OS amputation-the OPO, CMB, and siphon lobes could be suppressed by knockdown of the hsp70 and dnaJb4 genes, but not the bag3 gene, suggesting that BAG3 is not required for regeneration. The results are consistent with demonstrations of the importance of similar heat shock genes in other regenerating systems, including planarian whole body regeneration [ 42 , 43 ], starfish arm regeneration [ 44 ], zebrafish fin regeneration [ 45 ], Xenopus tadpole hindlimb regeneration [ 46 ], and mouse liver regeneration [ 47 ]. Our studies contribute a new understanding of the process of Ciona unidirectional regeneration by identifying stress in the BS as a key event necessary for initiating the distal regeneration program.…”

Section: Discussionsupporting

confidence: 87%

Differentially expressed chaperone genes reveal a stress response required for unidirectional regeneration in the basal chordate Ciona

Jeffery

et al. 2023

BMC Biol

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Background Unidirectional regeneration in the basal chordate Ciona intestinalis involves the proliferation of adult stem cells residing in the branchial sac vasculature and the migration of progenitor cells to the site of distal injury. However, after the Ciona body is bisected, regeneration occurs in the proximal but not in the distal fragments, even if the latter include a part of the branchial sac with stem cells. A transcriptome was sequenced and assembled from the isolated branchial sacs of regenerating animals, and the information was used to provide insights into the absence of regeneration in distal body fragments. Results We identified 1149 differentially expressed genes, which were separated into two major modules by weighted gene correlation network analysis, one consisting of mostly upregulated genes correlated with regeneration and the other consisting of only downregulated genes associated with metabolism and homeostatic processes. The hsp70, dnaJb4, and bag3 genes were among the highest upregulated genes and were predicted to interact in an HSP70 chaperone system. The upregulation of HSP70 chaperone genes was verified and their expression confirmed in BS vasculature cells previously identified as stem and progenitor cells. siRNA-mediated gene knockdown showed that hsp70 and dnaJb4, but not bag3, are required for progenitor cell targeting and distal regeneration. However, neither hsp70 nor dnaJb4 were strongly expressed in the branchial sac vasculature of distal fragments, implying the absence of a stress response. Heat shock treatment of distal body fragments activated hsp70 and dnaJb4 expression indicative of a stress response, induced cell proliferation in branchial sac vasculature cells, and promoted distal regeneration. Conclusions The chaperone system genes hsp70, dnaJb4, and bag3 are significantly upregulated in the branchial sac vasculature following distal injury, defining a stress response that is essential for regeneration. The stress response is absent from distal fragments, but can be induced by a heat shock, which activates cell division in the branchial sac vasculature and promotes distal regeneration. This study demonstrates the importance of a stress response for stem cell activation and regeneration in a basal chordate, which may have implications for understanding the limited regenerative activities in other animals, including vertebrates.

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Section: Discussionsupporting

confidence: 87%

Differentially expressed chaperone genes reveal a stress response required for unidirectional regeneration in the basal chordate Ciona

Jeffery

et al. 2023

BMC Biol

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“…Fluorescent real time RT-PCR (qRT-PCR) was performed three times with independent RNA samples. Planarian elongation factor 2 ( Djef2 ) was utilized as the reference gene in all of the experiments ( Ma et al, 2017 ). Expression ratios were determined with the 2 −ΔΔCT method, which was described by Livak and Schmittgen (2001) .…”

Section: Methodsmentioning

confidence: 99%

Identification of Autophagy-Related Gene 7 and Autophagic Cell Death in the Planarian Dugesia japonica

Zhang

Song

et al. 2018

Front. Physiol.

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Planarians undergo continuous body size remodeling under starvation or during regeneration. This process likely involves autophagy and autophagic cell death, but this hypothesis is supported by few studies. To test this hypothesis, we cloned and characterized autophagy-related gene 7 (Atg7) from the planarian Dugesia japonica (DjAtg7). The full-length cDNA of DjAtg7 measures 2272 bp and includes a 2082-bp open reading frame encoding 693 amino acids with a molecular weight of 79.06 kDa. The deduced amino acid sequence of DjAtg7 contains a conserved ATP-binding site and a catalytic active site of an E1-like enzyme belonging to the ATG7 superfamily. DjAtg7 transcripts are mainly expressed in intestinal tissues of the intact animals. After amputation, DjAtg7 was highly expressed at the newly regenerated intestinal branch on days 3–7 of regeneration and in the old tissue of the distal intestinal branch on day 10 of regeneration. However, knockdown of DjAtg7 by RNAi did not affect planarian regeneration and did not block autophagosome formation, which indicates that autophagy is more complex than previously expected. Interestingly, TEM clearly confirmed that autophagy and autophagic cell death occurred in the old tissues of the newly regenerated planarians and clearly revealed that the dying cell released vesicles containing cellular cytoplasmic contents into the extracellular space. Therefore, the autophagy and autophagic cell death that occurred in the old tissue not only met the demand for body remodeling but also met the demand for energy supply during planarian regeneration. Collectively, our work contributes to the understanding of autophagy and autophagic cell death in planarian regeneration and body remodeling.

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