Studies of the Transcription Elongation Factor Spt4/5

Gene transcription is essential for life and plays a critical role in the ability of cells to respond to regulatory cues. Spt5 is a highly conserved transcriptional regulator and interacts with many proteins implicated in human diseases, including cancer and AIDS. This project will investigate the mechanism by which Spt5 interacts with RNA to coordinate regulatory processes that occur during transcription and will provide insights into diseases associated with gene transcription and processing.

Gene transcription is an essential process for life and plays a critical role in the ability of cells to respond to regulatory cues and to adopt distinct behaviours and fates. In eukaryotes, protein-encoding genes are transcribed by RNA polymerase II with the aid of general transcription factors. In addition, a large number of gene-specific regulatory proteins are needed to facilitate the independent regulation of the many thousands of protein coding genes. Spt5 is an ancient and essential regulator of transcription elongation, assisting RNA polymerase to maintain processivity of transcription. In eukaryotes, Spt5 forms a complex with Spt4. Spt4/5 associates with a wide range of proteins implicated in human cancers including chromatin regulators and RNA processing factors. These associations suggest that Spt4/5 plays a central role in connecting gene expression to RNA processing. However, the mechanism by which these interactions occur, and their role in regulating gene expression is poorly understood.

Professor Vrielink’s studies indicate Spt4/5 binds specific RNA sequences, implicated in RNA processing events and may function in the recruitment of RNA processing factors to the polymerase. He aims to test this hypothesis in vitro and in vivo. The team is characterizing the RNA binding profile using SELEX and RNA electromobility shift assays. In addition they are studying the in vivo relationship between the RNA binding capability, specificity and transcript level or processing events using microarray data, RNA-Seq analysis, reporter gene assays and iCLIP approaches. Finally they are characterizing the structures of Spt4/5 with target RNAs using X-ray crystallography. These studies will provide a detailed understanding of the role of the Spt4/5 in RNA interaction and in linking transcription with RNA processing events.


  • Professor Grant Hartzog, University of California Santa Cruz