SCARECROW-LIKE3 regulates the transcription of gibberellin-related genes by acting as a transcriptional co-repressor of GAI-ASSOCIATED FACTOR1
SCARECROW-LIKE3 regulates the transcription of gibberellin-related genes by acting as a transcriptional co-repressor of GAI-ASSOCIATED FACTOR1
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DOI：
10.1007/s11103-020-01101-z
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发表时间：
2021-01-21
影响因子：
5.1
通讯作者：
Fukazawa, Jutarou
中科院分区：
文献类型：
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作者：
Ito, Takeshi;Fukazawa, Jutarou
GRAS[赤霉素不敏感(GAI)、GA1-3抑制子(RGA)和稻草人(SCR)]蛋白是一类植物特有的转录调节蛋白家族，在发育和信号转导中发挥不同的作用。GRAS家族della蛋白作为生长抑制因子，通过抑制赤霉素(GA)信号来响应发育和环境信号。DELLA还作为转录因子GAI相关因子1(GAF1)/不确定DOMAIN2(IDD2)的共同激活因子，GAF1-DELLA复合体激活GAF1靶基因的转录。在没有della的情况下，GAF1也与转录共抑制物TPL相互作用，Della是GAF1-TPL复合体，抑制靶基因的转录。稻草人-LIKE3(SCL3)是GRAS家族的另一个成员，被认为通过与IDD的竞争性相互作用抑制IDD-della复合体的转录活性。在这里，我们还揭示了SCL3通过抑制活性而不是通过竞争性抑制GAF1-della相互作用来抑制GAF1-della复合体的转录激活。此外，GAF1对SCL3的抑制作用不依赖于TPL。Della的GRAS结构域具有转录激活活性，而SCL3的GRAS结构域具有抑制活性。SCL3还抑制GAF1-RGA融合蛋白的转录活性。免疫共沉淀法和酵母三杂交实验结果表明SCL3可能与GAF1和DELLA形成三元复合体。这些发现为了解DELLA调节的GA信号和转录抑制机制提供了重要信息。
GRAS [GIBBERELLIN-INSENSITIVE (GAI), REPRESSOR OF ga1-3 (RGA) and SCARECROW (SCR)] proteins are a family of plant-specific transcriptional regulators that play diverse roles in development and signaling. GRAS family DELLA proteins act as growth repressors by inhibiting gibberellin (GA) signaling in response to developmental and environmental cues. DELLAs also act as co-activators of transcription factor GAI-ASSOCIATED FACTOR1 (GAF1)/INDETERMINATE DOMAIN2 (IDD2), the GAF1-DELLA complex activating transcription of GAF1 target genes. GAF1 also interacts with TOPLESS (TPL), a transcriptional co-repressor, in the absence of DELLA, the GAF1-TPL complex repressing transcription of the target genes. SCARECROW-LIKE3 (SCL3), another member of the GRAS family, is thought to inhibit transcriptional activity of the IDD-DELLA complex through competitive interaction with IDD. Here, we also revealed that SCL3 inhibits transcriptional activation by the GAF1-DELLA complex via repression activity rather than via competitive inhibition of the GAF1-DELLA interaction. Moreover, the repression activity of SCL3 was enhanced by GAF1 in a TPL-independent manner. While the GRAS domain of DELLA has transcriptional activation activity, that of SCL3 has repression activity. SCL3 also inhibited transcriptional activity of GAF1-RGA fusion proteins. Results from the co-immunoprecipitation assays and the yeast three-hybrid assay suggested the possibility that SCL3 forms a ternary complex with GAF1 and DELLA. These findings provide important information on DELLA-regulated GA signaling and new insight into the transcriptional repression mechanism.