Raghavan V, Kamalay J C
Department of Plant Biology, Ohio State University, Columbus 43210.
Planta. 1993 Jan;189(1):1-9. doi: 10.1007/BF00201336.
A library of complementary DNA (cDNA) clones has been prepared from poly(A)+RNA of spores of the sensitive fern, Onoclea sensibilis L. By differential hybridization with labeled probes made to poly(A)+RNA of spores, gametophytes and leaves, two spore-specific clones (pOSS68 and pOSS194) were selected and characterized. Northern blot analysis showed that RNA sequences homologous to the two cDNA clones first appear in the post-meiotic spore and increase in abundance during spore maturity. Both RNA sequences decay during photoinduced germination of the spores and do not reappear in the gametophytes. In spores imbibed in the dark under conditions which do not favor germination, no significant decrease in pOSS194-mRNA abundance is noted. In contrast, the decrease in pOSS68 mRNA in dark-imbibed spores parallels that observed in photoinduced spores. The predicted amino-acid sequence of pOSS194 has a striking similarity to the early light-inducible proteins expressed during the greening of etiolated pea and barley seedlings, whereas that of pOSS68 shows some homology to proteins encoded by late-embryogenesis-abundant mRNAs of angiosperm embryos.
已从敏感蕨类植物荚果蕨（Onoclea sensibilis L.）孢子的聚腺苷酸加尾RNA（poly(A)+RNA）制备了互补DNA（cDNA）克隆文库。通过与针对孢子、配子体和叶片的聚腺苷酸加尾RNA制备的标记探针进行差异杂交，筛选并鉴定了两个孢子特异性克隆（pOSS68和pOSS194）。Northern印迹分析表明，与这两个cDNA克隆同源的RNA序列首先出现在减数分裂后的孢子中，并在孢子成熟过程中丰度增加。在孢子光诱导萌发期间，这两种RNA序列均会降解，且在配子体中不会重新出现。在不利于萌发的条件下于黑暗中吸胀的孢子中，未观察到pOSS194 - mRNA丰度有显著下降。相比之下，黑暗吸胀孢子中pOSS68 mRNA的下降与光诱导孢子中观察到的情况相似。pOSS194预测的氨基酸序列与黄化豌豆和大麦幼苗绿化过程中表达的早期光诱导蛋白有显著相似性，而pOSS68的氨基酸序列与被子植物胚胎晚期胚胎发生丰富mRNA编码的蛋白质有一些同源性。
