Identification and analysis of a Marsupenaeus japonicus ferritin that is regulated at the transcriptional level by WSSV infection

• A ferritin homolog from M. japonicus was identified.
• Ferritin mRNA was ubiquitously expressed in tissues of M. japonicus.
• M. japonicus ferritin transcript level was regulated by WSSV infection.
• WSSV copies increased along with degeneration of tissues in the infected shrimp.

Marsupenaeus japonicus is a shrimp species of great value in the Chinese aquaculture industry. Given the susceptibility to viral diseases, research efforts have focused on the molecular characteristics of the shrimp's immune mechanisms. Ferritin is well known for its iron storage function, but studies have also addressed its immune function in response to pathogens. In this study, an M. japonicus ferritin cDNA was identified by homology cloning and rapid amplification of cDNA ends-PCR. The full-length cDNA is 1244 bp long and contains an open reading frame (513 bp) that encodes a highly conserved protein of 170 amino acids. Quantitative real-time PCR detection of ferritin revealed high expression in eight tested tissues, with the highest levels in hemocytes—consistent with the iron storage capacity of ferritin. We infected M. japonicus with white spot syndrome virus and validated the model by viral copy analysis and histopathology, which demonstrated an increase in viral copies along with acute degeneration of tissues. Transcripts of ferritin increased by 3.1-fold, 2.1-fold, and 1.5-fold in the hepatopancreas, gill, and midgut at 24 h post-injection, suggesting that ferritin played an important role in the immune response of M. japonicus.