Rapid induction of specific mRNAs by auxin in pea epicotyl tissue.
Rapid induction of specific mRNAs by auxin in pea epicotyl tissue.
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DOI：
10.1016/0022-2836(85)90280-3
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发表时间：
1985-05
影响因子：
5.6
通讯作者：
Athanasios Theologis;Thanh V. Huynh;R. W. Davis
中科院分区：
文献类型：
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作者：
Athanasios Theologis;Thanh V. Huynh;R. W. Davis
通过对载体 λgt10 中构建的 cDNA 文库进行差异噬菌斑过滤杂交，分离出与豌豆上胚轴组织中三种吲哚乙酸 (IAA) 诱导型 mRNA 互补的 DNA 序列。克隆pIAA6与编码先前鉴定的翻译产物多肽6(Mr22,000)的mRNA杂交，克隆pIAA4/5与编码多肽4和5(分别为Mr23,000和25,000)的一种或两种mRNA杂交。随后使用 cDNA 克隆来表征激素介导的 mRNA 积累。 mRNA 的诱导速度很快，在暴露于 IAA 后 15 分钟内，并且对生长素具有特异性。厌氧、热和冷应激不会诱导 mRNA。其他植物激素，如赤霉酸、激动素、脱落酸和乙烯也不能引起或干扰 IAA 诱导的 mRNA 积累。用 IAA 处理两小时后，激素调节的 mRNA 诱导水平比对照水平至少高出 50 至 100 倍，并且积累是 (1) 不依赖于蛋白质合成，(2) 完全被 α-鹅膏蕈碱消除，(3) 不是由于预先存在的 RNA 的聚腺苷酸化，以及 (4) 不依赖于 IAA 和梭菌素诱导的 H+ 分泌。 IAA诱导的mRNA在去除IAA后三小时内恢复到对照水平，并且激素调节基因主要在7日龄黄化豌豆幼苗的第三和第二节间表达。数据表明IAA增加了特定mRNA的量，而不是改变了预先存在的mRNA的可翻译性。生长素诱导的 H+ 分泌似乎在介导诱导过程中没有潜在作用，可能是激素诱导的生物合成活性增强的结果。 IAA 介导的 mRNA 诱导是已知的任何植物生长调节剂中最快的，并且可能代表对生长素的主要激素反应。
DNA sequences complementary to three indoleacetic acid (IAA)-inducible mRNAs in pea epicotyl tissue were isolated by differential plaque filter hybridization of cDNA libraries constructed in the vector λgt10. Clone pIAA6 hybridized to an mRNA encoding the previously identified translational product polypeptide 6 (Mr22,000), and clone pIAA4/5 hybridized to one or two mRNAs, encoding polypeptides 4 and 5 (Mr23,000 and 25,000, respectively). The cDNA clones were subsequently used to characterize the hormonally mediated mRNA accumulation. The induction of the mRNAs was rapid, within 15 minutes of exposure to the IAA, and specific to auxins. Anaerobiosis, heat and cold stress did not induce the mRNAs. Other plant hormones, such as gibberellic acid, kinetin, abscisic acid and ethylene were also unable to cause or interfere with the IAA-induced mRNA accumulation. The hormonally regulated mRNAs were induced at least 50 to 100-fold above control levels after two hours of treatment with IAA and the accumulation was (1) independent of protein synthesis, (2) completely abolished by α-amanitin, (3) not due to polyadenylylation of pre-existing RNAs, and (4) independent of IAA and fusicoccin-induced H+secretion. The IAA-induced mRNAs returned to control levels within three hours after removal of IAA, and the hormonally regulated genes were primarily expressed in the third and second internode of the seven-day-old etiolated pea seedling.The data indicate that IAA increases the amount of specific mRNAs rather than alters the translatability of pre-existing mRNAs. Auxin-induced H+secretion appears not to have a potential role in mediating the induction and perhaps is a consequence of the enhanced biosynthetic activity induced by the hormone. The IAA-mediated mRNA induction is the fastest known for any plant growth regulator and may represent a primary hormonal response to auxin.