The effect of endogenous mRNA levels on co-suppression in tomato
The effect of endogenous mRNA levels on co-suppression in tomato
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DOI：
10.1016/s0014-5793(04)00280-7
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发表时间：
2004-04-09
期刊：
影响因子：
3.5
通讯作者：
Grierson, D
中科院分区：
文献类型：
--
作者：
Han, YH;Griffiths, A;Grierson, D
将截短的多聚半乳糖醛酸酶（PG）转基因导入番茄植株中，通过转录后基因沉默引起成熟果实中内源和PG转基因的小干扰RNA（siRNA）的产生和共抑制。为了测试对内源PG mRNA水平的共抑制的可能影响，我们通过与具有降低的PG的两个成熟调节突变体（Never-成熟（Nr，与野生型相比，类似于10%内源PG mRNA）和成熟抑制剂（rin，与1%内源PG mRNA类似））和野生型（作为对照）杂交，将PG转基因从PG沉默系（野生型背景）转移。PG转基因在具有高PG mRNA背景（野生型）的细胞中引起转基因和内源PG基因的强烈共抑制，并且沉默似乎与较高的转基因拷贝数和/或特定的转基因座相关。在具有低内源PG mRNA积累（Nr）的细胞中，与表达没有显著降低的转基因相比，内源PG基因被优先抑制。转基因的表达在非常低的PG背景（rin）中也没有减少，其中内源性PG几乎检测不到。在具有所有三种PG背景水平的所有分析品系中，siRNA在叶和绿色果实中积累，其中内源PG基因不转录。在大多数品系中相对丰富的siRNA产生与特定的转基因插入物有关。这些结果表明，一定的阈值水平的内源PG mRNA的截短的PG转基因和内源PG基因的共抑制或广泛沉默的转基因是必需的。(C)2004年由Elsevier B. V.代表欧洲生物化学学会联合会出版。
Introduction of truncated polygalacturonase (PG) transgenes into tomato plants caused the production of small interfering RNAs (siRNAs) and co-suppression of both the endogenous and PG transgenes in ripening fruits by post-transcriptional gene silencing. In order to test the possible effect on co-suppression of the endogenous PG mRNA level, we transferred the PG transgenes from a PG-silenced line (wild type background) by crossing to two ripening regulatory mutants with reduced PG: Never-ripe (Nr, similar to10% endogenous PG mRNA compared to wild type) and ripening-inhibitor (rin, similar to1% endogenous PG mRNA) and to wild type (as a control). The PG transgenes caused strong co-suppression of the transgenes and the endogenous PG gene in cells with high PG mRNA background (wild type) and silencing appeared to be linked with higher transgene copy number and/or a particular transgene locus. In cells with low endogenous PG mRNA accumulation (Nr), the endogenous PG gene was preferentially suppressed compared to the transgenes, whose expression was not reduced significantly. The expression of the transgenes was also not reduced in the very low PG background (rin), in which endogenous PG was barely detectable. In all the analysed lines with all three PG background levels, siRNAs accumulated in leaves and green fruits, in which the endogenous PG gene is not transcribed. The relatively abundant production of siRNAs in most of the lines was linked with a particular transgene insert. These results suggest that a certain threshold level of endogenous PG mRNA is required for the co-suppression of the truncated PG transgenes and the endogenous PG gene or for extensive silencing of the transgenes. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.