Transcription elongation factor which binds histone H3 and enhances transcription elongation by RNA polymerase II (RNAPII). Promotes the activation of the myogenic gene program by entailing erasure of the repressive H3K27me3 epigenetic mark through stabilization of the chromatin interaction of the H3K27 demethylase KDM6A. Plays an important role during early patterning and somitogenesis of the embryo. Expressed throughout the blastoderm early in development. Highly expressed in the developing brain at 24 hours post-fertilization (hpf), and at lower levels in the rest of the embryo. Belongs to the SPT6 family. Contaminating sequence. Potential poly-A sequence.