Early transcription elongation factor of RNA pol II, NGN section
Spt5p and prokaryotic NusG are shown to contain a novel 'NGN' domain. The combined NGN and KOW motif regions of Spt5 form the binding domain with Spt4. Spt5 complexes with Spt4 as a 1:1 heterodimer snf this Spt5-Spt4 complex regulates early transcription elongation by RNA polymerase II and has an imputed role in pre-mRNA processing via its physical association with mRNA capping enzymes. The Schizosaccharomyces pombe core Spt5-Spt4 complex is a heterodimer bearing a trypsin-resistant Spt4-binding domain within the Spt5 subunit.