Expression patterns of GASA genes in Arabidopsis thaliana:: the GASA4 gene is up-regulated by gibberellins in meristematic regions
Expression patterns of GASA genes in Arabidopsis thaliana:: the GASA4 gene is up-regulated by gibberellins in meristematic regions
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DOI：
10.1023/a:1005938624418
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发表时间：
1998-04-01
影响因子：
5.1
通讯作者：
Herzog, M
中科院分区：
文献类型：
--
作者：
Aubert, D;Chevillard, M;Herzog, M
先前在拟南芥中发现的 GASA 基因家族属于在单子叶和双子叶植物中发现的一类广泛存在的基因，所有这些基因在结构上都与来自番茄的原始 GA 调节的 GAST1 基因相关。它们编码功能未知的小肽（97 至 112 个残基），共享一个 60 个氨基酸的保守 C 端结构域，其中包含 12 个保守的半胱氨酸残基，定义了一种不相关的模式 其他已知的富含半胱氨酸的基序。 Northern印迹杂交分析揭示了三个基因在开花、长角果发育和种子萌发过程中的顺序表达。在花蕾中检测到 GASA4 转录本。授粉后约五天，GASA1 转录物在长角果中显着积累，并且与长角果发育阶段的 GA 生物合成高峰相关。 GASA3转录本在长角果成熟阶段末期积累，并且转录本仍然存在于干燥种子中，但在吸胀过程中迅速降解。此外，GASA4 基因在萌发后再次活跃转录，并且这种表达取决于 GA 缺陷突变体中 GA 的存在。免疫印迹分析证实了花蕾、幼苗和根中存在 GASA4 基因产物。我们关注 GASA4 基因并表征其表达。上游区域（-890 至 +128）与 GUS 报告基因融合。在转基因拟南芥中，主要在所有分生组织区域检测到 GASA4/GUS 表达，包括营养、花序和花分生组织，以及初生根和侧根尖。在缺乏 GA 的背景 (ga1-3) 中，仅在存在 GA 的情况下才能检测到营养分生组织中的 GUS 活性。在根和花分生组织中，外源 GA 略微增强了基础 GUS 活性。有趣的是，在提供外源 GA 的 ga1-3 突变体以及野生型中，GA 强烈抑制 GUS 扩展子叶和叶子的活性。 GA 依赖性分生组织特异性表达模式表明 GASA4 蛋白在细胞分裂而不是细胞伸长中发挥作用。
The GASA gene family previously identified in Arabidopsis belongs to a wide-spread class of genes found in mono- and dicotyledonous plants, all structurally related to the original GA-regulated GAST1 gene from tomato, They encode small peptides (97 to 112 residues) of unknown function sharing a 60 amino acid conserved C-terminal domain comprising twelve conserved cysteine residues which define a pattern not related to other known cysteine-rich motifs. Northern blot hybridization analysis revealed sequential expression of three genes during flowering, silique development and seed germination. GASA4 transcripts were detected in flower buds. GASA1 transcripts markedly accumulated in siliques, about five days after pollination, and correlated with the peak of GA biosynthesis at this stage of silique development. GASA3 transcripts accumulated at the end of the maturation stage of the silique, and transcripts were still present in dry seeds but degraded rapidly during imbibition. In addition, the GASA4 gene was again actively transcribed after germination and this expression was shown to be dependent on the presence of GAs in GA-deficient mutants. Immunoblot analysis confirmed the presence of the GASA4 gene product in flower buds, seedlings and roots. We focused on the GASA4 gene and characterized its expression. The upstream region (-890 to +128) was fused to the GUS reporter gene. GASA4/GUS expression was detected in transgenic Arabidopsis primarily in all meristematic regions, including vegetative, inflorescence and floral meristems, as well as primary and lateral root tips. In a GA-deficient background (ga1-3), GUS activity in the vegetative meristem was detected only in the presence of supplied GA. In root and flower meristems, basal GUS activity was slightly enhanced by exogenous GA. Interestingly, GA strongly inhibit GUS activity in expanding cotyledons and leaves in ga1-3 mutants supplied with exogenous GAs, as well as in the wild type. The GA-dependent meristem-specific expression pattern suggests that the GASA4 protein plays a role in dividing cells rather than in elongating cells.