Landgren M, Zetterstrand M, Sundberg E, Glimelius K
Department of Plant Breeding Research, Uppsala Genetic Center, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Plant Mol Biol. 1996 Dec;32(5):879-90. doi: 10.1007/BF00020485.
Analyses of mitochondrial transcription and in organello translation were performed with the Brassica tournefortii cytoplasm. This cytoplasm causes alloplasmic male sterility when combined with the nuclear genomes of B. napus and B. juncea. Mitochondrial RNA and protein banding patterns were compared between the fertile wild species B. tournefortii, an alloplasmic male-sterile B. juncea line, an alloplasmic male-sterile B. napus line and an alloplasmic B. napus line with restored fertility. The analyses were carried out to identify differences in gene expression and to investigate whether alterations in gene expression accompanied male sterility. A difference in transcription patterns between the fertile B. tournefortii and the alloplasmic lines was found for the atp6 gene. The atp6 region was investigated further, since a similar alteration in atp6 transcription has been observed in two other Brassica cytoplasms which are associated with cytoplasmic male sterility (CMS). The additional longer atp6 transcript detected in the alloplasmic lines in the present study was found to contain an open reading frame (ORF) located downstream of the atp6 gene. DNA sequencing revealed that the ORF, orf263, could encode a protein with a predicted molecular weight of about 29 kDa. In organello analysis detected two proteins of 29 and 32 kDa respectively, which were found only in the alloplasmic lines. Furthermore, the 32 kDa protein accompanied male sterility since it was absent in alloplasmic plants restored to fertility. The protein analysis might indicate that orf263 is translated and causes CMS.
利用芥菜型油菜细胞质进行了线粒体转录和体外翻译分析。当这种细胞质与甘蓝型油菜和芥菜型油菜的核基因组结合时，会导致异质体雄性不育。对可育野生种芥菜型油菜、异质体雄性不育芥菜型油菜品系、异质体雄性不育甘蓝型油菜品系以及育性恢复的异质体甘蓝型油菜品系的线粒体RNA和蛋白质条带模式进行了比较。进行这些分析是为了确定基因表达的差异，并研究基因表达的改变是否伴随着雄性不育。在atp6基因方面，发现可育的芥菜型油菜与异质体系之间的转录模式存在差异。由于在另外两种与细胞质雄性不育（CMS）相关的甘蓝型油菜细胞质中也观察到了atp6转录的类似改变，因此对atp6区域进行了进一步研究。在本研究中，在异质体系中检测到的额外较长的atp6转录本被发现包含一个位于atp6基因下游的开放阅读框（ORF）。DNA测序显示，该ORF（orf263）可编码一种预测分子量约为29 kDa的蛋白质。体外分析分别检测到了两种分子量为29 kDa和32 kDa的蛋白质，它们仅在异质体系中出现。此外，32 kDa的蛋白质伴随着雄性不育，因为在育性恢复的异质体植物中不存在。蛋白质分析可能表明orf263被翻译并导致CMS。
