Cloning and chromosomal mapping of nuclear genes encoding chloroplast and cytosolic glyceraldehyde-3-phosphate-dehydrogenase from Arabidopsis thaliana

Both cDNA and genomic clones for the nuclear genes encoding chloroplast (cp) (gapA and gapB) and cytosolic (gapC) glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from Arabidopsis thaliana have been isolated and characterized. Genomic Southern-blot analyses indicate that there is only one copy of each gapA, gapB and gapC gene in A. thaliana. Comparison of the deduced amino acid (aa) sequences shows that the A and B subunits are highly similar (80% positional aa identity), while there is less similarity between the cp and cytosolic subunits (45% aa identity). These relationships are consistent with the idea that the cp and cytosolic GAPDHs evolved from different lineages, as suggested in our previous study of tobacco GAPDHs Shih et al., Cell 47 (1986) 73-80]. In addition, the chromosomal locations for the three gap genes were determined by restriction fragment length polymorphism mapping; the three gap genes are not closely linked, gapA (55.8 cM) and gapC (0.0 cM) are on chromosome 3, and gapB (51.3 cM) is on chromosome 1.