Full-length transcriptome sequencing and identification and immune response of TRIM genes in Dabry's sturgeon (Acipenser dabryanus)

Acipenser dabryanus, also called Yangtze sturgeon or Dabry?s sturgeon, is an endemic species restricted to the upper reaches of the Yangtze River in China. In the present study, we conducted the first full-length transcriptome analysis of A. dabryanus by the use of SMRT sequencing technology. Transcriptome sequencing generated a total of 155,348 unigenes with a mean length of 2996 bp. A total of 131,711 (84.78%) unigenes were annotated in various databases and comparative analysis was performed between A. dabryanus and its the related species. Based on the sequence information, three members in the tripartite motif (TRIM) family, namely, TRIM32, TRIM36 and TRIM71, were identified. The full-length TRIM genes encoded polypeptides with a typical TRIM structure: a RING domain, one or two B-box domains, and variable domains at the C-terminus. Gene expression profile analysis showed that the three TRIM genes were constitutively expressed in A. dabryanus, and the highest expression levels of TRIM32 and TRIM36 were found in the brain, while TRIM71 was predominantly expressed in the muscle. Upon challenge with the bacterial pathogen Edwardsiella tarda, significant upregulation of TRIMs was observed in both mucosal and systemic-associated immune tissues. Our data revealed the possible functional role of TRIMs in both mucosal and systemic defence of A. dabryanus in the immune response against bacterial infection.