RNA-SEQ REVEALS SPECIFIC GENE EXPRESSION PATTERN IN THE KEY STAGES OF INTESTINE REGENERATION IN SEA CUCUMBER APOSITICHOPUS JAPONICAS

Yaqing Chang*, Xiangxiang Zhang, Meng Chen, Yi Wang, Yaoyao Zhan
 
Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture, Dalian Ocean University, Dalian, Liaoning, 116023
yqchang@dlou.edu.cn

 

Sea cucumbers, one of the most important economic marine species in Asian countries, have a special defense mechanism, named evisceration. The eviscerated sea cucumbers are capable of regenerating lost tissues (such as intestine, respiratory trees, and gonad) when the environment is appropriate. Many studies on sea cucumber regeneration have been conducted in the field of histology, cytology, molecular and genetic biology. Further work to clarify the regeneration mechanisms in sea cucumbers is still needed. Here, we used the sea cucumber Apostichopus japonicas as a model to study regeneration and performed 4 transcriptomes (C-intest, C-trees, H-intest and H-trees) by IlluminaHiseq 2000 platform to reveal the changes of gene expression associated with regeneration of the intestine in A. japonicas at before evisceration and 3, 5, 7, 10, 14, 17, 21 and 28 days post evisceration (dpe).

Approximately 40 million reads were sequenced in each transcriptome. In total, we obtained 109411 unigenes and 238279 transcripts. There were 21730 (19.86%) and 7652 (6.99%) unigenes can be annotated in terms of GO and KO, respectively. 1780 differentially expressed genes (DEGs) were found in the transcriptome of the regenerating intestine, of which 898 were up-regulated and 882 were down-regulated genes. As for the trasnscriptomes of regenerating respiratory trees, 4,321 DEGs with 1780 up-regulated and 2541 down-regulated genes were found. 20 candidate DEGs related to regeneration were selected to validate the sequencing results by Real-time PCR. 27788 simple sequence repeats (SSRs) were identified in the 4 transcriptomes. We obtained 501243, 506846, 525677 and 495644 single nucleotide polymorphisms (SNPs) in C-intest, C-trees, H-intest and H-trees, respectively.

In conclusion, through the high throughput sequencing technology, our study demonstrated a comprehensive characterization of A. japonicas and obtained a series of regeneration-related gene candidates. A large number of potential genetic markers were identified as well. The transcriptomes of this study provides an important foundation for future study of regeneration mechanisms of sea cucumber at the genetics and molecular level.