A Dorsal homolog (FcDorsal) in the Chinese shrimp Fenneropenaeus chinensis is responsive to both bacteria and WSSV challenge

Rel/NFκB is a family of transcription factors. In the present study, a Rel/NFκB family member, Dorsal homolog (FcDorsal) was cloned from the Chinese shrimp Fenneropenaeus chinensis. The full length cDNA of FcDorsal consists of 1627 bp, revealed a 1071 bp open reading frame encoding 357 aa. The predicted molecular weight (MW) of the deduced amino acid sequence of FcDorsal was 39.78 kDa, and its theoretical pI was 8.85. Amino acid sequence analysis showed that FcDorsal contains a Rel homolog domain (RHD) and an IPT/TIG (Ig-like, plexins and transcriptions factors) domain. The signature sequence of dorsal protein existed in the deduced amino acid sequence. Spatial expression profiles showed that FcDorsal had the highest expression level in the hemocytes and lymphoid organ (Oka). The expression profiles in the hemocytes and lymphoid organ were apparently modulated when shrimp were stimulated by bacteria or WSSV. Both Gram-positive (G+) bacteria (Micrococcus lysodeikticus) and Gram-negative (G−) bacteria (Vibrio anguillarium) injection to shrimp caused the up-regulation of FcDorsal at the transcription level. DsRNA approach was used to study the function of FcDorsal and the data showed that FcDorsal was related to the transcription of Penaeidin 5 in shrimp. The present data provide clues that FcDorsal might play potential important roles in the innate immunity of shrimp. Through comparison of the expression profiles between FcDorsal and another identified Rel/NFκB member (FcRelish) in shrimp responsive to WSSV challenge, we speculate that FcDorsal and FcRelish might play different roles in shrimp immunity.