The role of mRNA 5' end capping in the transcriptional regulation of gene expression in eukaryotic cells.

5' RNA m7 G帽是RNA聚合酶II依赖性（Pol II）转录物的必要修饰。有效的mRNA加帽对于mRNA稳定性是至关重要的，因为它保护RNA免于5 '-3'降解。帽还作为帽结合复合物（CBC）的平台发挥作用，所述帽结合复合物对于细胞RNA代谢（包括核输出、降解和翻译）是必需的。尽管m7 G帽在mRNA生物发生中具有关键功能，但对其在转录和最终在基因表达中的直接作用知之甚少。先前的报道表明，mRNA帽的缺陷可能会影响从转录起始到延伸的过渡或触发过早的转录终止。因此，该项目将在模式生物酿酒酵母中研究mRNA帽、加帽酶和加帽过程如何调节真核细胞中的转录和RNA合成。学生将采用染色质免疫沉淀（ChIP-seq）分析来测试Pol II磷酸异构体的基因组位置，以及帽缺陷细胞中稳态（RNA-seq和直接RNA-seq）和新生RNA（4 tU RNA-seq）的RNA分析。这些方法将提供m7 G帽和加帽如何影响真核细胞中的核RNA生物学的全面分析。该项目的结果将揭示RNA帽是否以及如何与5 '-3'共转录降解相关，并将定义Pol II转录基因的加帽、转录进展和转录终止之间的相关性。

The 5' RNA m7G cap is an essential modification of the RNA Polymerase II-dependent (Pol II) transcripts. An efficient mRNA capping is crucial for mRNA stability as it protects the RNA from 5'-3' degradation. The cap functions also as a platform for the Cap Binding Complex (CBC) which is essential for cellular RNA metabolism including nuclear export, degradation, and translation. Although the m7G cap has a crucial function in the mRNA biogenesis, very little is known about its direct role in transcription and ultimately, in gene expression. Previous reports indicate that defects in mRNA capping may affect the transition from transcription initiation to elongation or trigger premature transcription termination. Thus, the project will investigate in the model organism Saccharomyces cerevisiae how the mRNA cap, the capping enzymes and the capping process regulate transcription and RNA synthesis in eukaryotic cells. The student will employ chromatin immunoprecipitation (ChIP-seq) analysis to test genomic positions of Pol II phosphoisoforms as well as RNA analyses of steady-state (RNA-seq and direct RNA-seq) and nascent RNA (4tU RNA-seq) in cap-deficient cells. These approaches will provide a comprehensive analysis of how m7G cap and the capping impact nuclear RNA biology in eukaryotic cells. The outcomes of this project will reveal if and how RNA cap is related to 5'-3' co-transcriptional degradation and will define a correlation between capping, transcription progression and transcription termination of Pol II-transcribed genes.