EXPRESSION IN SPIROPLASMA-CITRI OF AN EPITOPE CARRIED ON THE G-FRAGMENT OF THE CYTADHESIN-P1-GENE FROM MYCOPLASMA-PNEUMONIAE

We have previously described the use of the replicative form (RF) of S piroplasma citri virus SpV1 as a vector for cloning and expressing for eign genes in S. citri, an organism which reads UGA as a tryptophan co don (C. Stamburski, J. Renaudin, and J. M. Bove, J. Bacteriol. 173:222 5-2230, 1991). We now report cloning and expression in S. citri of the G fragment of cytadhesin P1 gene from Mycoplasma pneumoniae. The G fr agment was inserted in the SpV1 RF downstream of a synthetic ribosome binding site and introduced into S. citri by electroporation. Northern (RNA) blot analyses showed that in S. citri, the G fragment was trans cribed from an SpV1 RF promoter as a 1.2-kb mRNA. The translation prod uct was detected by Western blotting (immunoblotting) with a rabbit an tiserum raised against total proteins from M. pneumoniae (strain FH) a nd was proved to be P1 specific by using monoclonal antibodies specifi c for the G region of the P1 protein. The apparent molecular mass of t he polypeptide (24.5 kDa) indicates that in S. citri, the G fragment w as fully translated in spite of the seven UGA codons present in the re ading frame.