Akagi H, Sakamoto M, Shinjyo C, Shimada H, Fujimura T
Plant Biotechnology Laboratory, Mitsui Toatsu Chemicals, Inc., Mobara, Japan.
Curr Genet. 1994 Jan;25(1):52-8. doi: 10.1007/BF00712968.
Asymmetric cell-fusion of the japonica cultivar of Oryza sativa (rice) with cytoplasmic-male-sterile (CMS) plants bearing cytoplasm derived from Chinsurah Boro II, resulted in two classes of cytoplasmic hybrids (cybrids), fertile and CMS. Southern-blot analysis of the mitochondrial DNA (mtDNA) indicates recombination events around a number of genes; however, the appearance of the CMS character is tightly correlated to reorganization around the atp6 gene, suggesting recombination downstream from the atp6 gene is involved in CMS. The nucleotide sequence downstream from atp6 contains a pseudogene which was probably created by recombination of the mitochondrial genome. Sense and antisense transcripts of the downstream region of atp6 were found in CMS- and restored CMS (fertile)-lines, but not in the normal (fertile) line. In the CMS line, several antisense transcripts of the atp6 gene were also found. However, in the restored line which contains a nuclear-encoded gene, Rf-1, the levels of these transcripts were lower than in the CMS line. These results suggest abnormal transcripts of the atp6 gene produced in the antisense direction may be involved in CMS, and that products of the nuclear-encoded restorer gene may reduce abnormal transcription in this region of the mitochondrial genome.
将栽培稻粳稻品种与携带源自钦苏拉·博罗II型细胞质的细胞质雄性不育（CMS）植株进行不对称细胞融合，产生了两类细胞质杂种（cybrids），即可育型和CMS型。线粒体DNA（mtDNA）的Southern杂交分析表明，多个基因周围发生了重组事件；然而，CMS性状的出现与atp6基因周围的重组紧密相关，这表明atp6基因下游的重组参与了CMS过程。atp6基因下游的核苷酸序列包含一个假基因，它可能是由线粒体基因组重组产生的。在CMS系和恢复育性的CMS（可育）系中发现了atp6基因下游区域的正义和反义转录本，但在正常（可育）系中未发现。在CMS系中，还发现了几个atp6基因的反义转录本。然而，在含有核编码基因Rf-1的恢复系中，这些转录本的水平低于CMS系。这些结果表明，反义方向产生的atp6基因异常转录本可能参与了CMS过程，并且核编码恢复基因的产物可能会减少线粒体基因组该区域的异常转录。
