Heterogeneity of Chloroplast DNA in Rice

벼 엽록체 DNA의 이질성

Plant chloroplast DNA exists as an unique circular structure in which large single copy(LSC) region and small single copy (SSC) region are separated by large inverted repeat sequences (IRS). It has been known that the unique existence of inverted repeat sequences in chloroplast DNA has no relation with the stability of the chloroplast DNA, but causes the inversion between inverted repeat its biological significance has not been understood so far. In rice, several gene clusters have been cloned and sequenced which contain ribulose-5-biophosphate car-boxylase large subunit (rbcL). Especially, one rbcL gene is linked with rp12 gene which is located in the IRS region in one of the gene clusters. By comparison of nucleotide sequence, the two genes are found to be linked through 151 bp repeat sequence which is homologous to the rp123 gene in IRS region. The repeat sequence is found to be located 3' downstream of rfcL gene and near psbA gene in LSC region. The existence of these repeat sequences and the presence of gene clusters caused by the gene rearrangement thorough the repeat sequence provide a possible which is found to be dispersed chloroplast DNA provide the model system to explaine the heterogeneity of the chloroplast DNA in rice in term of gene rearrangement.