Lack of evidence for the presence of an interferon in invertebrate

In vertebrates, the interferon (IFN) response is the primary form of innate antiviral defense. Previously (2005), a partial cDNA which could encode an interferon-like protein (IntlP) is reported in shrimp, later Rosa et al. (2008) argue that this partial cDNA should encode a portion of insect mitochondrial ATP synthase (MAS) B-chain. Recently (2009), it is demonstrated IntlP also possess antibacterial activity beside antiviral activity reported before. Lacking of a consensus opinion to the question of whether this gene encodes IntlP or MAS, we try to provide more evidences to identify this gene exactly. Here we obtain the full length cDNAs of IntlP/ MAS in Litopenaeus vannamei, and perform the tissue distribution and induced expression analysis. Our results confirm that IntlP is coded by a mistaken ORF and the actual protein indeed is a L. vannamei mitochondrial ATP synthase (LvMAS) whose function is unknown in antiviral responses.