Recombinational properties of the Saccharomyces cerevisiae FLP gene expressed in Escherichia coli.

The FLP gene from the 2-μm DNA of Saccharomyces cerevisiae is shown to be functionally expressed in Escherichia coli leading to site-specific intramolecular as well as intermolecular recombination between IR sequences. The expression was achieved under control of a low expression as well as a high expression E. coli promoter. The FLP gene was found to complement in trans a Flp(-) plasmid and promote its interconversion.By the use of a low Flp expression plasmid, it could be shown that the rate of interconversion of a Flp(-) plasmid by complementation in trans, was lower than that of a Flp(+) plasmid, suggesting that in addition to the IR sequences another cis-acting function exists.Expression of the FLP gene fused to the lac promoter in an in vitro system yielded two polypeptides with apparent molecular weights of 44,000 and 37,000. The 37,000 dalton polypeptide can also be produced from Flp(-) plasmids and is generated from a translation start within the FLP gene. The 44,000 dalton polypeptide is considered to represent the FLP gene product.