Transcription elongation factor SPT5

SPT5 (SUPT5H) is a transcription elongation factor that functions as a core component of the DRB sensitivity-inducing factor complex (DSIF). It regulates mRNA processing and transcription elongation by RNA polymerase II, including positive regulation of mRNA capping and cooperative suppression of transcriptional pausing with the NELF complex (UniProt: O00267). These activities facilitate assembly of elongation-competent RNA polymerase II and support efficient transcriptional progression, with the protein also playing specialized roles in HIV-1 transcriptional activation.

SPT5 operates broadly in transcriptional regulation across tissues and cell types, with no specific disease associations listed in UniProt. The protein is well-characterized for its roles in both pausing and elongation phases of transcription, depending on phosphorylation state and protein complex interactions.

In Alzheimer's Disease, SPT5 shows modest upregulation in post-mortem AD brain compared to age-matched controls, with a mean log2 fold-change of 0.18 (Chaparral AD proteomics). This elevation was detected across one subcellular fraction in a TMT-labeled proteomics study of human brain tissue. The functional significance of increased SPT5 in AD pathology remains to be elucidated.