Transcriptome analysis during early regeneration of Lumbriculus variegatus

Several annelid species exhibit an impressive regenerative capacity. Among them, Lumbriculus variegatus can reconstruct its entire body from only three original segments. Due to its high regenerative capability, L. variegatus has been proposed as a model for experimental studies of regeneration. However, limited molecular and genetic information is available for L. variegatus. Here, we conducted a transcriptome analysis during early regeneration of L. variegatus using RNA-sequencing. We generated 61 million Illumina reads during early regeneration of L. variegatus. These reads were assembled into two transcriptomes, one of which was selected for annotation. The transcriptome contained 138,008 genes and 164,769 transcripts. We identified 44,097 non-coding transcripts and 65,692 candidate cds with an ORF. Functional annotation with GO categories was possible for 36,494 predicted proteins. One hundred and thirty-six transcripts were differentially expressed during early regeneration, of which 111 were upregulated and 25 were downregulated. GO enrichment analysis showed that carboxyllyase activity, amino acid metabolism, and metabolism of glycosides were enriched. vdr, which encodes for a Vitamin D3 receptor was upregulated during early regeneration. This gene has been implicated in regeneration in vertebrates. On the other hand, vwde, a gene associated with the proximal-distal determination of the blastema, was downregulated. Unexpectedly, the Glutamine synthetase coding gene was also downregulated, but this gene was found to be upregulated during regeneration in other oligochaetes. Further functional characterization of these genes in L. variegatus will contribute to our understanding of regeneration. This transcriptome will be a resource for studies aimed at the identification of the conserved molecular mechanisms underlying the regeneration.