Brander K A, Kuhlemeier C
Institute of Plant Physiology, University of Berne, Switzerland.
Plant Mol Biol. 1995 Feb;27(4):637-49. doi: 10.1007/BF00020219.
A pollen-specific sequence, NeIF-4A8, has been isolated from a cDNA library from mature pollen of Nicotiana tabacum cv. Samsun. NeIF-4A8 is a full-length cDNA whose deduced amino acid sequence exhibits high homology to the eucaryotic translation initiation factor eIF-4A from mouse, Drosophila and tobacco. eIF-4A is an RNA helicase which belongs to the supergene family of DEAD-box proteins. Northern blot analysis with a gene-specific probe showed strict anther-specific expression of NeIF-4A8 starting at microspore mitosis. With antibodies raised against tobacco eIF-4A the presence of abundant eIF-4A-related proteins in developing anthers and pollen grains was demonstrated. The genomic analysis shows that the coding region is split by three introns whereas a large, fourth intron is situated in the 5'-untranslated region. A promoter construct with 2137 bp of upstream sequence fused to the GUS reporter gene was used to confirm that the expression is confined to the haploid cells within the anther. NeIF-4A8 is a prime candidate formediating translational control in the developing male gametophyte.
从烟草品种萨姆逊成熟花粉的cDNA文库中分离出了一个花粉特异性序列NeIF-4A8。NeIF-4A8是一个全长cDNA，其推导的氨基酸序列与来自小鼠、果蝇和烟草的真核生物翻译起始因子eIF-4A具有高度同源性。eIF-4A是一种RNA解旋酶，属于DEAD-box蛋白的超基因家族。用基因特异性探针进行的Northern印迹分析表明，NeIF-4A8从微孢子有丝分裂开始就严格在花药中特异性表达。用针对烟草eIF-4A产生的抗体证明了在发育中的花药和花粉粒中存在大量与eIF-4A相关的蛋白质。基因组分析表明，编码区被三个内含子隔开，而一个大的第四个内含子位于5'-非翻译区。一个带有2137 bp上游序列与GUS报告基因融合的启动子构建体被用于证实该表达局限于花药内的单倍体细胞。NeIF-4A8是在发育中的雄配子体中介导翻译控制的主要候选者。
