Spt4 Promotes Pol I Processivity and Transcription Elongation

Genes (Basel). 2021 Mar 12;12(3):413. doi: 10.3390/genes12030413.


RNA polymerases (Pols) I, II, and III collectively synthesize most of the RNA in a eukaryotic cell. Transcription by Pols I, II, and III is regulated by hundreds of trans-acting factors. One such protein, Spt4, has been previously identified as a transcription factor that influences both Pols I and II. Spt4 forms a complex with Spt5, described as the Spt4/5 complex (or DSIF in mammalian cells). This complex has been shown previously to directly interact with Pol I and potentially affect transcription elongation. The previous literature identified defects in transcription by Pol I when SPT4 was deleted, but the necessary tools to characterize the mechanism of this effect were not available at the time. Here, we use a technique called Native Elongating Transcript Sequencing (NET-seq) to probe for the global occupancy of Pol I in wild-type (WT) and spt4△ Saccharomyces cerevisiae (yeast) cells at single nucleotide resolution in vivo. Analysis of NET-seq data reveals that Spt4 promotes Pol I processivity and enhances transcription elongation through regions of the ribosomal DNA that are particularly G-rich. These data suggest that Spt4/5 may directly affect transcription elongation by Pol I in vivo.

Keywords: RNA polymerase I; Spt4; rRNA; ribosome; transcription.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Chromosomal Proteins, Non-Histone / genetics
  • DNA, Ribosomal / genetics
  • DNA-Directed RNA Polymerases / genetics
  • Nuclear Proteins / genetics*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics*
  • Transcription Factors / genetics
  • Transcription, Genetic / genetics*
  • Transcriptional Elongation Factors / genetics*


  • Chromosomal Proteins, Non-Histone
  • DNA, Ribosomal
  • Nuclear Proteins
  • SPT4 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Transcriptional Elongation Factors
  • SPT5 transcriptional elongation factor
  • DNA-Directed RNA Polymerases