Distinctive Nuclear Localization Signals in the Oomycete Phytophthora sojae.
Distinctive Nuclear Localization Signals in the Oomycete Phytophthora sojae.
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DOI：
10.3389/fmicb.2017.00010
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发表时间：
2017
影响因子：
5.2
通讯作者：
Tyler BM
中科院分区：
文献类型：
--
作者：
Fang Y;Jang HS;Watson GW;Wellappili DP;Tyler BM
迄今为止，卵菌中靶向蛋白质到核的核定位信号（NLS）尚未被定义，但已被假定为与高等真核生物中相同。在这里，我们使用大豆病原体大豆疫霉作为模型来调查这些序列的卵菌。通过建立一种可靠的基于共聚焦显微镜的体内NLS检测方法，我们发现许多典型的单组分和双组分经典NLS（cNLS）在大豆疫霉中介导的核输入很差。我们发现cNLS对大豆疫霉核蛋白的有效定位需要在远端位点添加额外的碱性氨基酸或与其他NLS合作。我们发现，另一个充分表征的NLS，脯氨酸-酪氨酸NLS（PY-NLS）的几个代表也在大豆疫霉中功能不佳。为了表征大豆疫霉中的PY-NLS，我们通过实验确定了三种大豆疫霉核定位蛋白中功能性PY-NLS所需的残基。这些结果表明，功能性大豆疫霉PY-NLS包括额外的碱性残基簇，用于有效的核输入。最后，对几种高度保守的大豆疫霉核蛋白（包括核糖体蛋白和核心组蛋白）的分析表明，与哺乳动物或酵母中的直系同源物相比，这些蛋白质表现出类似但更强的核靶向序列要求。
To date, nuclear localization signals (NLSs) that target proteins to nuclei in oomycetes have not been defined, but have been assumed to be the same as in higher eukaryotes. Here, we use the soybean pathogen Phytophthora sojae as a model to investigate these sequences in oomycetes. By establishing a reliable in vivo NLS assay based on confocal microscopy, we found that many canonical monopartite and bipartite classical NLSs (cNLSs) mediated nuclear import poorly in P. sojae. We found that efficient localization of P. sojae nuclear proteins by cNLSs requires additional basic amino acids at distal sites or collaboration with other NLSs. We found that several representatives of another well-characterized NLS, proline-tyrosine NLS (PY-NLS) also functioned poorly in P. sojae. To characterize PY-NLSs in P. sojae, we experimentally defined the residues required by functional PY-NLSs in three P. sojae nuclear-localized proteins. These results showed that functional P. sojae PY-NLSs include an additional cluster of basic residues for efficient nuclear import. Finally, analysis of several highly conserved P. sojae nuclear proteins including ribosomal proteins and core histones revealed that these proteins exhibit a similar but stronger set of sequence requirements for nuclear targeting compared with their orthologs in mammals or yeast.