Upregulated transcription of phenoloxidase genes in the pharynx and endostyle of Ciona intestinalis in response to LPS

We investigated the role of phenoloxidases (POs) in ascidians inflammatory reaction, a components of acopper-containing protein family involved in invertebrate immune system. In Ciona intestinalis two phenoloxidases(CinPO-1, CinPO-2) have been sequenced. In the present study, real time PCR analysis showedthat both CinPO-1 and CinPO-2 genes were modulated by LPS inoculation suggesting that they are inducibleand highly expressed in the inflamed pharynx. In situ hybridization disclosed CinPO-1 and CinPO-2transcripts in pharynx hemocytes (granulocytes) and, mainly, in unilocular refractile granulocytes (URG)which mainly populated the inflamed tunic matrix. Interestingly, the genes are also upregulated by LPS inthe endostyle (zones 7, 8 and 9) that is considered homolog to the vertebrate thyroid.