Kim M H, Shin D I, Park H S, Chung I K
Faculty of Life Resources, Catholic University of Taegu, Kyungsan, Korea.
Mol Cells. 2001 Dec 31;12(3):329-35.
S RNases are products of the S locus that are expressed in the stylar tissue of Lycopersicon peruvianum with the gametophytic self-incompatibility (SI) system. Two S RNases (S12 and Sa) with RNase activity from the S12Sa genotype of L. peruvianum were purified using gel filtration and cation-exchange chromatography. The molecular masses of the two RNases, S12 and Sa, were 21 and 23.1 kDa, respectively. The specific activities of S12 and Sa for torula yeast rRNA as a substrate were 8,500 and 6,000 units/ml, respectively. Of various reagents tested for RNase activities, ZnSO4 and CuSO4 were found to remarkably reduce its activity. The growth of S12Sa pollen was inhibited when it was cultured in a pollen germination medium that contained the purified S12 RNase. The result suggested that the S RNase was either a probable inhibitor of pollen growth or controlled pollen growth. Additionally, 512Sa pollens germinated well in vitro in a germination medium that contained S12 RNase in the presence of ZnSO4 and CuSO4. Our finding suggests that the treatment of S RNase with its inhibitor destroys the SI ability on an in vitro self-pollen growth test.
S核糖核酸酶是茄科番茄属秘鲁番茄配子体自交不亲和（SI）系统中花柱组织中S位点的产物。利用凝胶过滤和阳离子交换色谱法，从秘鲁番茄S12Sa基因型中纯化出两种具有核糖核酸酶活性的S核糖核酸酶（S12和Sa）。两种核糖核酸酶S12和Sa的分子量分别为21 kDa和23.1 kDa。以圆酵母rRNA为底物时，S12和Sa的比活性分别为8500和6000单位/毫升。在测试的各种核糖核酸酶活性试剂中，发现硫酸锌和硫酸铜能显著降低其活性。当S12Sa花粉在含有纯化的S12核糖核酸酶的花粉萌发培养基中培养时，其生长受到抑制。结果表明，S核糖核酸酶可能是花粉生长的抑制剂或控制花粉生长。此外，在含有S12核糖核酸酶的萌发培养基中添加硫酸锌和硫酸铜时，512Sa花粉在体外萌发良好。我们的研究结果表明，在体外自花花粉生长试验中，用其抑制剂处理S核糖核酸酶会破坏SI能力。
