Transcription elongation factor SPT6 (SUPT6H)

Transcription elongation factor which binds histone H3 and plays a key role in the regulation of transcription elongation and mRNA processing. Enhances the transcription elongation by RNA polymerase II (RNAPII) and is also required for the efficient activation of transcriptional elongation by the HIV-1 nuclear transcriptional activator, Tat.

Apart from chaperoning histones in transcription, acts to transport and splice mRNA by forming a complex with IWS1 and the C-terminal domain (CTD) of the RNAPII subunit RPB1 (POLR2A). The SUPT6H:IWS1:CTD complex recruits mRNA export factors (ALYREF/THOC4, EXOSC10) in addition to histone modifying enzymes (for example, SETD2), to ensure appropriate mRNA splicing, efficient mRNA export and elongation-coupled H3K36 methylation, a signature chromatin markers of active transcription.