Organ-specific and Agamous-regulated expression and glycosylation of a pollen tube growth-promoting protein.
Organ-specific and Agamous-regulated expression and glycosylation of a pollen tube growth-promoting protein.
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DOI：
10.1073/pnas.93.9.3853
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发表时间：
1996-04
影响因子：
11.1
通讯作者：
A. Cheung;X. Zhan;Hui Wang;Hen-Ming Wu
中科院分区：
文献类型：
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作者：
A. Cheung;X. Zhan;Hui Wang;Hen-Ming Wu
传递组织特异性蛋白（TTS）是位于烟草雌蕊花柱传递组织细胞外基质中的一种促进和吸引花粉管生长的糖蛋白。TTS蛋白骨架的表观分子质量约为28 kDa，而糖基化的花柱TTS蛋白的表观分子质量在50 - 100 kDa之间。TTS mrna和蛋白是在表达花菜花叶病毒（CaMV） 35S启动子- tts2转基因或CaMV 35S启动子-NAG1 （NAG1 = Nicotiana tabacum Agamous gene）转基因的烟草植株中异位产生的。然而，在这两种类型的转基因植物中，TTS mRNA和蛋白的积累模式以及产生的TTS蛋白的质量是不同的。在35S-TTS转基因植物中，TTS mrna和蛋白在营养和花组织中组成性地积累。然而，异位表达的TTS蛋白在这些转基因植物中积累为低糖基化蛋白，表观分子质量在30 - 50 kDa之间。这表明产生高度糖基化的TTS蛋白的能力仅限于花柱传递组织。在35S-NAG转基因植物中，NAG1 mrna在营养和花组织中组成性积累，而TTS mrna在这些植物的萼片中被诱导。此外，在这些转基因35S-NAG植物的萼片中，分子质量在50- 100 kda范围内的高度糖基化的TTS蛋白积累。这些结果表明，烟草NAGI基因与其他尚未确定的调控因子一起，控制着TTS基因的表达和细胞糖基化TTS蛋白的能力，这些蛋白通常在雄蕊发育途径中表达很晚，并在花发育的最后阶段发挥作用。转基因35S-NAG植株的萼片也支持有效的花粉萌发和管状生长，类似于雌蕊通常发生的情况，这种能力与最高水平的50至100 kda糖基化TTS蛋白的积累有关。
Transmitting tissue-specific (TTS) protein is a pollen tube growth-promoting and attracting glycoprotein located in the stylar transmitting tissue extracellular matrix of the pistil of tobacco. The TTS protein backbones have a deduced molecular mass of about 28 kDa, whereas the glycosylated stylar TTS proteins have apparent molecular masses ranging between 50 and 100 kDa. TTS mRNAs and proteins are ectopically produced in transgenic tobacco plants that express either a cauliflower mosaic virus (CaMV) 35S promoter-TTS2 transgene or a CaMV 35S-promoter-NAG1 (NAG1 = Nicotiana tabacum Agamous gene) transgene. However, the patterns of TTS mRNA and protein accumulation and the quality of the TTS proteins produced are different in these two types of transgenic plants. In 35S-TTS transgenic plants, TTS mRNAs and proteins accumulate constitutively in vegetative and floral tissues. However, the ectopically expressed TTS proteins in these transgenic plants accumulate as underglycosylated protein species with apparent molecular masses between 30 and 50 kDa. This indicates that the capacity to produce highly glycosylated TTS proteins is restricted to the stylar transmitting tissue. In 35S-NAG transgenic plants, NAG1 mRNAs accumulate constitutively in vegetative and floral tissues, and TTS mRNAs are induced in the sepals of these plants. Moreover, highly glycosylated TTS proteins in the 50- to 100-kDa molecular mass range accumulate in the sepals of these transgenic, 35S-NAG plants. These results show that the tobacco NAGI gene, together with other yet unidentified regulatory factors, control the expression of TTS genes and the cellular capacity to glycosylate TTS proteins, which are normally expressed very late in the pistil developmental pathway and function in the final stage of floral development. The sepals in the transgenic 35S-NAG plants also support efficient pollen germination and tube growth, similar to what normally occurs in the pistil, and this ability correlates with the accumulation of the highest levels of the 50- to 100-kDa glycosylated TTS proteins.