Localisation of genes for four ATP synthase subunits in pea chloroplast DNA

Abstract

The genes for four subunits of the chloroplast ATP synthase, alpha, beta and epsilon of CF1 and subunit III of CF0, have been located in pea chloroplast DNA using hybridisation of fragments of genes for homologous wheat ATP synthase subunits and cell-free coupled transcription-translation of pea chloroplast DNA or cloned restriction fragments. The genes are arranged in two clusters, which are 50 kbp apart. The gene for the beta subunit is located close to that for the epsilon subunit and the gene for the alpha subunit is approximately 2 kbp away from that for the CF0 subunit III gene. The genes for the alpha subunit and the CF0 subunit III are transcribed in the same direction. The beta subunit gene is close to the gene for the large subunit of ribulose 1,5-bisphosphate (RuBP) carboxylase but the two genes are transcribed divergently. The arrangement of the genes in two clusters is similar to that found in other plant species, although pea chloroplast DNA has no large inverted repeat sequence and has undergone extensive rearrangements relative to chloroplast DNAs which contain the large inverted repeat sequences.