Dinoflagellates have a generally large number of genes but only a small percentage of these are annotated as transcription factors. Cold shock domain (CSD) containing proteins (CSPs) account for roughly 60% of these. CSDs are not prevalent in other eukaryotic lineages, perhaps suggesting a lineage-specific expansion of this type of transcription factors in dinoflagellates, but there is little experimental data to support a role for dinoflagellate CSPs as transcription factors. Here we evaluate the hypothesis that dinoflagellate CSPs can act as transcription factors by binding double-stranded DNA in a sequence dependent manner. We find that both electrophoretic mobility shift assay (EMSA) competition experiments and selection and amplification binding (SAAB) assays indicate binding is not sequence specific for four different CSPs from two dinoflagellate species. Competition experiments indicate all four CSPs bind to RNA better than double-stranded DNA. Dinoflagellate CSPs do not share the nucleic acid binding properties expected for them to function as bone fide transcription factors. We conclude the transcription factor complement of dinoflagellates is even smaller than previously thought suggesting that dinoflagellates have a reduced dependance on transcriptional control compared to other eukaryotes.

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评估来自 Symbiodinium kawagutii 和 Lingulodinium polyedra 的四种鞭毛藻冷休克域蛋白的核酸结合活性

甲藻通常具有大量基因，但其中只有一小部分被注释为转录​​因子。含有冷休克域 (CSD) 的蛋白质 (CSP) 约占其中的 60%。CSD 在其他真核生物谱系中并不普遍，这可能表明这种类型的转录因子在甲藻中存在谱系特异性扩增，但几乎没有实验数据支持甲藻 CSP 作为转录因子的作用。在这里，我们评估了以下假设：甲藻 CSP 可以通过以依赖序列的方式结合双链 DNA 来充当转录因子。我们发现电泳迁移率变化测定 (EMSA) 竞争实验和选择和扩增结合 (SAAB) 测定都表明结合不是来自两种鞭毛藻物种的四种不同 CSP 的序列特异性。竞争实验表明，所有四种 CSP 与 RNA 的结合都比双链 DNA 更好。甲藻 CSP 不具有预期它们作为骨转录因子发挥作用的核酸结合特性。我们得出结论，甲藻的转录因子补体甚至比以前认为的还要小，这表明与其他真核生物相比，甲藻对转录控制的依赖性降低。甲藻 CSP 不具有预期它们作为骨转录因子发挥作用的核酸结合特性。我们得出结论，甲藻的转录因子补体甚至比以前认为的还要小，这表明与其他真核生物相比，甲藻对转录控制的依赖性降低。甲藻 CSP 不具有预期它们作为骨转录因子发挥作用的核酸结合特性。我们得出结论，甲藻的转录因子补体甚至比以前认为的还要小，这表明与其他真核生物相比，甲藻对转录控制的依赖性降低。