Identification and characterization of the gene encoding the mitochondrial elongation factor G in rice

A plant nuclear gene coding for a mitochondrial elongation factor G (mEF-G) was cloned from a cDNA library and genomic library of rice (Oryza sativa L.). This DNA sequence predicts a 757-amino-acid protein exhibiting 79%, 55% and 49% homology to Arabidopsis thaliana, Saccharomyces cerevisiae and rat mEF-G respectively, 53% homology to the elongation factor G in Escherichia coli and 43% homology to soybean chloroplast elongation factor G. The deduced amino acid sequence contains the characteristic motifs shared by all GTP binding proteins. Comparison of the sequence of the genomic clone to that of the cDNA clone revealed that this gene is split nineteen times by introns, although the gene of Arabidopsis is split seventeen times by introns. Some of the introns found in the rice genome are relatively long and they result in a long gene with a size of approximately 15 kb.