Location of the single gene for elongation factor Tu on the Euglena gracilis chloroplast chromosome.

The structural gene for elongation factor Tu (EF-Tu) has been mapped by heterologous hybridization to a 2900 base pair sequence of Euglena gracilis Klebs Strain Z Pringsheim chloroplast DNA within the EcoRI fragment, Eco N. The hybridization probes were obtained from a HhaI restriction fragment containing internal sequences to Escherichia coli EF-Tu, located in the tufA gene locus, and from an EcoRI restriction fragment of chloroplast DNA from the eukaryotic algae Chlamydomonas reinhardii, containing the 3' end of the chloroplast EF-Tu gene. This is the second identified protein gene locus to be mapped on the E. gracilis chloroplast genome, and the first using prokaryotic DNA as a probe.