InterPro domain: IPR041980

Spt5, an eukaryotic ortholog of NusG, contains multiple KOW motifs at its C terminus. Spt5 is involved in transcription elongation and termination. The KOW domain is known as an RNA-binding motif that is shared so far among some families of ribosomal proteins, the essential bacterial transcriptional elongation factor NusG, the eukaryotic chromatin elongation factor Spt5, the higher eukaryotic KIN17 proteins and Mtr4 [ 1 ]. Unlike bacterial NusG with its single KOW motif, eukaryotic Spt5 has multiple KOW domains. There are four KOW motifs in yeast Spt5, whereas human Spt5 has six [ 2 ]. Spt5 KOW domains play critical roles in recruitment of multiple other eukaryotic transcription elongation and RNA biogenesis factors and additionally are involved in the binding of the eukaryotic Spt5 proteins to RNA polymerases [ 3 , 4 , 5 ].

1. KOW: a novel motif linking a bacterial transcription factor with ribosomal proteins. Trends Biochem. Sci. 21, 425-6
2. Yeast transcription elongation factor Spt5 associates with RNA polymerase I and RNA polymerase II directly. J. Biol. Chem. 286, 18825-33
3. The Spt4-Spt5 complex: a multi-faceted regulator of transcription elongation. Biochim. Biophys. Acta 1829, 105-15
4. Spt4/5 stimulates transcription elongation through the RNA polymerase clamp coiled-coil motif. Nucleic Acids Res. 38, 4040-51
5. A nexus for gene expression-molecular mechanisms of Spt5 and NusG in the three domains of life. J. Mol. Biol. 417, 13-27