AtSIG6 and other members of the sigma gene family jointly but differentially determine plastid target gene expression in Arabidopsis thaliana.
AtSIG6 and other members of the sigma gene family jointly but differentially determine plastid target gene expression in Arabidopsis thaliana.
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DOI：
10.3389/fpls.2014.00667
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发表时间：
2014
影响因子：
5.6
通讯作者：
Link G
中科院分区：
文献类型：
--
作者：
Bock S;Ortelt J;Link G
植物含有一个质体sigma因子的核基因家族，即与“细菌型”细胞器RNA聚合酶相关的蛋白质，并赋予正确启动子结合和转录起始的能力。关于sigma家族成员之间的“劳动分工”的问题仍未得到解决，包括它们的靶基因范围和它们在发育过程中的时间和空间活动。单个sigma基因在体内作用的线索主要来自对sigma敲除系的研究。然而，尽管有明显的优势，如果其他家族成员以冗余和/或补偿的方式行动，这种策略不一定能追踪突变表型和单个sigma基因之间的因果关系。我们努力通过拟南芥单突变体（重点是叶绿素缺乏的sig6系）的遗传杂交来降低复杂性，产生双敲除系。后者通常具有与亲本系相似的可见表型，但往往在质体和sigma基因的转录模式中受到更强烈的影响。由于三突变体在我们的生长条件下是致命的，我们利用含有非保守sigma区（UCR）序列的RNAi构建体转化单突变体和双突变体的策略。这些RNAi/敲除系在表型上与其亲本系相似，但其质体转录模式受到更强烈的影响。与亲本相比，sigma基因的表达模式既有相似之处，也有差异，转录本的数量减少或不变，而其他转录本的数量则增加（可能是补偿）。总之，我们的结果揭示了相当大的灵活性的基因活性在西格玛和质体基因表达水平。如果6个拟南芥sigma基因中的2-3个功能受损，则似乎达到了（仍然可行的）“基础状态”。
Plants contain a nuclear gene family for plastid sigma factors, i.e., proteins that associate with the “bacterial-type” organellar RNA polymerase and confer the ability for correct promoter binding and transcription initiation. Questions that are still unresolved relate to the “division of labor” among members of the sigma family, both in terms of their range of target genes and their temporal and spatial activity during development. Clues to the in vivo role of individual sigma genes have mainly come from studies of sigma knockout lines. Despite its obvious strengths, however, this strategy does not necessarily trace-down causal relationships between mutant phenotype and a single sigma gene, if other family members act in a redundant and/or compensatory manner. We made efforts to reduce the complexity by genetic crosses of Arabidopsis single mutants (with focus on a chlorophyll-deficient sig6 line) to generate double knockout lines. The latter typically had a similar visible phenotype as the parental lines, but tended to be more strongly affected in the transcript patterns of both plastid and sigma genes. Because triple mutants were lethal under our growth conditions, we exploited a strategy of transformation of single and double mutants with RNAi constructs that contained sequences from the unconserved sigma region (UCR). These RNAi/knockout lines phenotypically resembled their parental lines, but were even more strongly affected in their plastid transcript patterns. Expression patterns of sigma genes revealed both similarities and differences compared to the parental lines, with transcripts at reduced or unchanged amounts and others that were found to be present in higher (perhaps compensatory) amounts. Together, our results reveal considerable flexibility of gene activity at the levels of both sigma and plastid gene expression. A (still viable) “basal state” seems to be reached, if 2–3 of the 6 Arabidopsis sigma genes are functionally compromised.
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影响因子：
5.1
作者：
Lerbs-Mache, Silva
通讯作者：
Lerbs-Mache, Silva
DOI：
10.1073/pnas.94.26.14948
发表时间：
1997-12-23
影响因子：
11.1
作者：
Isono, K;Shimizu, M;Kobayashi, H
通讯作者：
Kobayashi, H
影响因子：
3.5
作者：
Morikawa, K;Shiina, T;Toyoshima, Y
通讯作者：
Toyoshima, Y
影响因子：
7.2
作者：
Clough, SJ;Bent, AF
通讯作者：
Bent, AF
DOI：
10.1111/j.1365-313x.2010.04138.x
发表时间：
2010-04
期刊：
The Plant journal : for cell and molecular biology
影响因子：
--
作者：
Schweer J;Türkeri H;Link B;Link G
通讯作者：
Link G