Spt4 promotes Pol I processivity and transcription elongation

The goal of this study was to determine the effect of Spt4 on transcription by Pol I in vivo. Therefore, Native Elongating Transcript Sequencing (NET-seq) was used to evaluate the occupancy of Pol I in wild-type and spt4△ strains. We determined that in spt4△ yeast, there was a processivity defect and Pol I accumulated at the 5' end of the 35S gene. Additionally, we observed that there was an enrichment for G-rich sequences just downstream of a high A content in the spt4△ strain, indicating that perhaps Spt4 plays a role in helping to propel Pol I through these regions of the rDNA. Altogether, this study suggests that Spt4 is an important transcription factor for Pol I by promoting polymerase processivity.本研究旨在探究Spt4对体内RNA聚合酶I（Pol I）转录的影响。为此，我们采用原生延伸转录本测序（Native Elongating Transcript Sequencing，NET-seq），对野生型与spt4△菌株中的Pol I结合占据水平进行评估。我们发现，在spt4△酵母中存在聚合酶持续合成能力缺陷，且Pol I在35S基因的5'端出现聚集。此外，我们观察到在spt4△菌株中，高A含量序列的紧邻下游区域存在富含G的序列富集现象，这提示Spt4可能在协助Pol I通过核糖体DNA（rDNA）的此类区域中发挥作用。综上，本研究表明，Spt4是调控Pol I转录的重要转录因子，其通过提升聚合酶的持续合成能力实现这一功能。