Yu L X, Nasrallah J, Valenta R, Parthasarathy M V
Section of Plant Biology, Cornell University, Ithaca, NY 14853, USA.
Plant Mol Biol. 1998 Mar;36(5):699-707. doi: 10.1023/a:1005971327353.
The actin cytoskeleton plays an important role in the growth of pollen tube. The actin-binding protein profilin could play a role in regulating the organization of the actin filaments. Using the RT-PCR technique, we isolated a cDNA clone (designated LePro 1) encoding profilin from pollen grains of tomato (Lycopersicon esculentum Mill. cv. Moneymaker). Sequence analysis of the insert shows 87% similarity to tobacco ntPro2, 78% to timothy grass profilin, 77% to Arabidopsis AthPRF4, 77% to maize ZmPro3, and 73% to birch profilin. Both quantitative PCR and RNA gel blot analyses demonstrated that LePro 1 is expressed in a tissue- or cell-type specific manner in the tomato plant. In situ hybridization of 2 microns thick anther sections using a non-radioactive labeling method reveals that LePro 1 is expressed only in pollen grains, with undetectable transcription in other parts of the anther or the other organs. Phylogenetic analysis of amino acid sequences of 18 plant profilins indicates that two distinct profilin gene classes are present in higher plants. One is pollen-specific, another is constitutive. LePro 1 belongs to the former class.
肌动蛋白细胞骨架在花粉管生长中起重要作用。肌动蛋白结合蛋白切丝蛋白可能在调节肌动蛋白丝的组织中发挥作用。利用RT-PCR技术，我们从番茄（Lycopersicon esculentum Mill. cv. Moneymaker）花粉粒中分离出一个编码切丝蛋白的cDNA克隆（命名为LePro 1）。对插入片段的序列分析表明，它与烟草ntPro2的相似性为87%，与梯牧草切丝蛋白的相似性为78%，与拟南芥AthPRF4的相似性为77%，与玉米ZmPro3的相似性为77%，与桦树切丝蛋白的相似性为73%。定量PCR和RNA凝胶印迹分析均表明，LePro 1在番茄植株中以组织或细胞类型特异性的方式表达。使用非放射性标记方法对2微米厚的花药切片进行原位杂交显示，LePro 1仅在花粉粒中表达，在花药的其他部分或其他器官中未检测到转录。对18种植物切丝蛋白氨基酸序列的系统发育分析表明，高等植物中存在两种不同的切丝蛋白基因类别。一种是花粉特异性的，另一种是组成型的。LePro 1属于前一类。
