Detection of LINE RT elements in the olive flounder (Paralichthys olivaceus) genome and expression analysis after infection with S. parauberis

Long interspersed nuclear elements (LINEs) are widely distributed in the vertebrate genome, and can be either beneficial or detrimental to the host genome. Here we identified three members of LINE RT elements in the olive flounder genome. They showed high amino acid sequence identity (89–99 %), and the sequences of LINE reverse transcriptase (RT) in olive flounder are closely related to those of coral grouper, European seabass, and three-spined stickleback. Real-time reverse transcription-polymerase chain reaction analysis indicated that expression of the OF (Olive flounder)-LINE Chr3-1 RT increased more in spleen than in other tissues after treatment with the pathogen Streptococcus parauberis. These data may form the basis for further studies on the function of retroelements in infected olive flounder.