FgPrp4 Kinase Is Important for Spliceosome B-Complex Activation and Splicing Efficiency in Fusarium graminearum.
FgPrp4 Kinase Is Important for Spliceosome B-Complex Activation and Splicing Efficiency in Fusarium graminearum.
复制标题
FgPrp4 激酶对于禾谷镰刀菌剪接体 B 复合物激活和剪接效率很重要
DOI：
10.1371/journal.pgen.1005973
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发表时间：
2016-04
期刊：
影响因子：
4.5
通讯作者：
Xu JR
中科院分区：
文献类型：
--
作者：
Gao X;Jin Q;Jiang C;Li Y;Li C;Liu H;Kang Z;Xu JR
PRP4编码剪接体组分中唯一的激酶。虽然Fgprp4突变体在裂变酵母和其他真核生物中是必不可少的基因，但它在小麦赤霉病菌镰刀菌（Fusarium graminearum）中存活。FgPRP4的缺失不会阻断内含子剪接，但会影响60%以上的禾粒镰刀菌基因的内含子剪接效率。Fgprp4突变体具有严重的生长缺陷，并产生自发的抑制因子，这些抑制因子在生长速率中恢复。通过与候选tr3 - snrnp成分基因的测序分析，在9株抑制菌株的PRP6、PRP31、BRR2和PRP8同源基因中发现了抑制基因突变。FgMSL1的Q86K突变通过抑制突变体S3的全基因组测序鉴定。尽管FgBrr2和FgPrp8中的两个抑制突变与其在酵母中的同源物相似，但Prp6和Prp31同源物或FgMSL1中的抑制突变尚未报道。有趣的是，在FgPrp6和FgPrp31中分别发现了四个和两个抑制突变，它们都位于保守的Prp4磷酸化位点附近，这表明这些突变可能与Prp4激酶磷酸化具有相似的作用。在FgPrp31中，R464处的无义突变导致包含所有保守的prp4磷酸化位点的c -末端130aa区域的截断。缺失分析表明，富含SR残基的n端310-aa在FgPrp4的定位和功能中起着关键作用。我们还对FgPrp4进行了磷酸化蛋白质组学分析，发现S289是其功能所必需的磷酸化位点。这些结果表明，FgPrp4对剪接效率至关重要，但对内含子剪接不是必需的，FgPrp4可能通过磷酸化tri-snRNP的其他组分来调节pre-mRNA剪接，尽管它本身可能被S289位点的磷酸化激活。
PRP4 encodes the only kinase among the spliceosome components. Although it is an essential gene in the fission yeast and other eukaryotic organisms, the Fgprp4 mutant was viable in the wheat scab fungus Fusarium graminearum. Deletion of FgPRP4 did not block intron splicing but affected intron splicing efficiency in over 60% of the F. graminearum genes. The Fgprp4 mutant had severe growth defects and produced spontaneous suppressors that were recovered in growth rate. Suppressor mutations were identified in the PRP6, PRP31, BRR2, and PRP8 orthologs in nine suppressor strains by sequencing analysis with candidate tri-snRNP component genes. The Q86K mutation in FgMSL1 was identified by whole genome sequencing in suppressor mutant S3. Whereas two of the suppressor mutations in FgBrr2 and FgPrp8 were similar to those characterized in their orthologs in yeasts, suppressor mutations in Prp6 and Prp31 orthologs or FgMSL1 have not been reported. Interestingly, four and two suppressor mutations identified in FgPrp6 and FgPrp31, respectively, all are near the conserved Prp4-phosphorylation sites, suggesting that these mutations may have similar effects with phosphorylation by Prp4 kinase. In FgPrp31, the non-sense mutation at R464 resulted in the truncation of the C-terminal 130 aa region that contains all the conserved Prp4-phosphorylation sites. Deletion analysis showed that the N-terminal 310-aa rich in SR residues plays a critical role in the localization and functions of FgPrp4. We also conducted phosphoproteomics analysis with FgPrp4 and identified S289 as the phosphorylation site that is essential for its functions. These results indicated that FgPrp4 is critical for splicing efficiency but not essential for intron splicing, and FgPrp4 may regulate pre-mRNA splicing by phosphorylation of other components of the tri-snRNP although itself may be activated by phosphorylation at S289.