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

• Two genes of phenoloxidases are transcribed in Ciona intestinalis.
• The POs mRNA were transcribed in the vessels hemocytes of the pharynx.
• The POs genes are also upregulated by LPS in the endostyle.
• Q-PCR analyses revealed that POs mRNA expression was upregulated by LPS challenge.

We investigated the role of phenoloxidases (POs) in ascidians inflammatory reaction, a components of a copper-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 showed that both CinPO-1 and CinPO-2 genes were modulated by LPS inoculation suggesting that they are inducible and highly expressed in the inflamed pharynx. In situ hybridization disclosed CinPO-1 and CinPO-2 transcripts 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 in the endostyle (zones 7, 8 and 9) that is considered homolog to the vertebrate thyroid.

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