MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824-1312.
Plant Physiol. 1991 Jul;96(3):980-4. doi: 10.1104/pp.96.3.980.
The only RNase genes that have been cloned from higher plants are those expressed in species that are known to exhibit self-incompatibility, such as the S genes of Nicotiana alata. In this report, we investigated whether the expression of this particular type of RNase gene is restricted to self-incompatible species, or if similar genes are expressed in other plants. Using a polymerase chain reaction approach we have identified a set of three putative RNase genes in the self-compatible plant Arabidopsis thaliana (L.) Heynh. ecotype Columbia. These A. thaliana genes, designated RNS1, RNS2, and RNS3, do not cross-hybridize to each other, and their products are homologous to both the S-gene RNases of N. alata and a set of related fungal enzymes. The A. thaliana RNS1, RNS2, and RNS3 genes encode transcripts of 1.1, 1.3, and 1.1 kilobases, respectively, and of the three genes, RNS2 is the most highly expressed in whole plants. The identification of the RNS genes in a self-compatible species suggests that this class of RNases is of general significance in RNA catabolism in higher plants.
从高等植物中克隆的唯一的 RNase 基因是那些在已知表现出自交不亲和性的物种中表达的基因，例如 Nicotiana alata 的 S 基因。在本报告中，我们调查了这种特殊类型的 RNase 基因的表达是否仅限于自交不亲和物种，或者是否在其他植物中表达类似的基因。我们使用聚合酶链反应方法在自交亲和植物拟南芥（L.）Heynh. 生态型哥伦比亚中鉴定了一组三个假定的 RNase 基因。这些拟南芥基因，分别命名为 RNS1、RNS2 和 RNS3，彼此之间不发生杂交，它们的产物与 N. alata 的 S 基因 RNases 和一组相关的真菌酶都具有同源性。拟南芥 RNS1、RNS2 和 RNS3 基因分别编码 1.1、1.3 和 1.1 千碱基的转录物，在这三个基因中，RNS2 在整个植物中表达水平最高。在自交亲和物种中鉴定出 RNS 基因表明，这类 RNases 在高等植物的 RNA 分解代谢中具有普遍意义。
