This family consists of several eukaryotic transcription elongation Spt4 proteins as well as archaebacterial RpoE2 [2]. Three transcription-elongation factors Spt4, Spt5, and Spt6 are conserved among eukaryotes and are essential for transcription via ...
This family consists of several eukaryotic transcription elongation Spt4 proteins as well as archaebacterial RpoE2 [2]. Three transcription-elongation factors Spt4, Spt5, and Spt6 are conserved among eukaryotes and are essential for transcription via the modulation of chromatin structure. Spt4 and Spt5 are tightly associated in a complex, while the physical association of the Spt4-Spt5 complex with Spt6 is considerably weaker. It has been demonstrated that Spt4, Spt5, and Spt6 play roles in transcription elongation in both yeast and humans including a role in activation by Tat. It is known that Spt4, Spt5, and Spt6 are general transcription-elongation factors, controlling transcription both positively and negatively in important regulatory and developmental roles [1]. RpoE2 is one of 13 subunits in the archaeal RNA polymerase. These proteins contain a C4-type zinc finger, and the structure has been solved in [3]. The structure reveals that Spt4-Spt5 binding is governed by an acid-dipole interaction between Spt5 and Spt4, and the complex binds to and travels along the elongating RNA polymerase. The Spt4-Spt5 complex is likely to be an ancient, core component of the transcription elongation machinery.