Liang Lizhi, Lai Zhao, Ma Wenshi, Zhang Yansheng, Xue Yongbiao
Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Beijing 100080, China.
Biochim Biophys Acta. 2002 Nov 13;1579(1):64-71. doi: 10.1016/s0167-4781(02)00507-9.
Several species of higher plants have been found to contain S-like ribonucleases (RNases), which are homologous to S-RNases controlling self-incompatibility. No S-like RNase genes have been isolated from self-incompatible Antirrhinum. To investigate the relationship between S- and S-like RNases, we cloned a gene named AhSL28 encoding an S-like RNase in Antirrhinum. Amino acid sequence, genomic structure and phylogenetic analyses indicated that AhSL28 is most similar to RNS2, an S-like RNase from Arabidopsis thaliana and formed a distinct subclass together with several other S-like RNases within the S-RNase superfamily. Unlike S-RNase genes in Antirrhinum, AhSL28 is not only expressed in pistils but also in leaves, petals, sepals and anthers, in particular, showing a strong expression in vascular tissues and transmitting track. Moreover, its RNA transcripts were induced during leaf senescence and phosphate (Pi) starvation but not by wounding, indicating that AhSL28 plays a role in remobilizing Pi and other nutrients, particularly when cells senesce and are under limited Pi conditions in Antirrhinum. Possible evolutionary relations of S- and S-like RNases as well as signal transduction pathways related to S-like RNase action are discussed.
已发现几种高等植物含有S类核糖核酸酶（RNases），它们与控制自交不亲和性的S-RNases同源。尚未从自交不亲和的金鱼草中分离出S类RNase基因。为了研究S-RNases和S类RNases之间的关系，我们在金鱼草中克隆了一个名为AhSL28的基因，该基因编码一种S类RNase。氨基酸序列、基因组结构和系统发育分析表明，AhSL28与拟南芥的一种S类RNase RNS2最为相似，并与S-RNase超家族中的其他几种S类RNases一起形成了一个独特的亚类。与金鱼草中的S-RNase基因不同，AhSL28不仅在雌蕊中表达，还在叶片、花瓣、萼片和花药中表达，特别是在维管组织和传递组织中表现出强烈的表达。此外，其RNA转录本在叶片衰老和磷酸盐（Pi）饥饿期间被诱导，但不受伤口诱导，这表明AhSL28在金鱼草中Pi和其他养分的再转运中起作用，特别是当细胞衰老且处于Pi有限的条件下时。本文还讨论了S-RNases和S类RNases可能的进化关系以及与S类RNase作用相关的信号转导途径。
