Ushijima K, Sassa H, Hirano H
Kihara Institute for Biological Research, Yokohama City University, Maioka 641-12, Totsuka-ku, Yokohama 244, Japan.
Gene. 1998 Apr 28;211(1):159-67. doi: 10.1016/s0378-1119(98)00105-x.
Genomic sequences of the self-incompatibility genes, the S-RNase genes, from two rosaceous species, Japanese pear and apple, were characterized. Genomic Southern blot and sequencing of a 4.5-kb genomic clone showed that the S4-RNase gene of Japanese pear is surrounded by repetitive sequences as in the case of the S-RNase genes of solanaceous species. The flanking regions of the S2- and Sf-RNase genes of apple were also cloned and sequenced. The 5' flanking regions of the three alleles bore no similarity with those of the solanaceous S-RNase genes, although the position and sequence of the putative TATA box were conserved. The putative promoter regions of the Japanese pear S4- and apple Sf-RNase genes shared a stretch of about 200bp with 80% sequence identity. However, this sequence was not present in the S2-RNase gene of apple, and thus it may reflect a close relationship between the S4- and Sf-RNase genes rather than a cis-element important in regulating gene expression. Despite the uniform pattern of expression of the rosaceous S-RNase genes, sequence motifs conserved in the 5' flanking regions of the three alleles were not found, implying that the cis-element controlling pistil specific gene expression also locates at the intragenic region or upstream of the analyzed promoter region.
对蔷薇科两个物种——日本梨和苹果的自交不亲和基因S-RNase基因的基因组序列进行了表征。基因组Southern杂交和一个4.5kb基因组克隆的测序表明，日本梨的S4-RNase基因如茄科物种的S-RNase基因一样，被重复序列所包围。苹果的S2-和Sf-RNase基因的侧翼区域也被克隆并测序。三个等位基因的5'侧翼区域与茄科S-RNase基因的5'侧翼区域没有相似性，尽管推定的TATA框的位置和序列是保守的。日本梨S4-和苹果Sf-RNase基因的推定启动子区域有一段约200bp的序列，序列同一性为80%。然而，该序列在苹果的S2-RNase基因中不存在，因此它可能反映了S4-和Sf-RNase基因之间的密切关系，而不是在调节基因表达中重要的顺式元件。尽管蔷薇科S-RNase基因的表达模式一致，但在三个等位基因的5'侧翼区域未发现保守的序列基序，这意味着控制雌蕊特异性基因表达的顺式元件也位于基因内区域或所分析启动子区域的上游。
