Recombinant Human AF-9 (MLLT3) YEATS Domain Fragment (aa 1-142) is a high-purity protein designed for chromatin biology and epigenetic research. This fragment fully encompasses the YEATS domain, enabling detailed study of histone recognition and transcriptional regulation mechanisms.

Protein AF-9 (MLLT3) is a crucial chromatin reader component of the super elongation complex (SEC) that enhances RNA polymerase II transcription by suppressing polymerase pausing. It specifically recognizes and binds acylated histone H3, showing preferential affinity for crotonylated histones (H3K9cr and H3K18cr) over acetylated or butyrylated forms. This recognition of crotonylation marks, which characterize active promoters and enhancers, allows AF-9 to recruit the SEC complex to chromatin and facilitate DOT1L-mediated H3K79 methylation. The protein plays a vital role in hematopoietic stem cell maintenance by preserving stemness through binding active gene transcription start sites and sustaining H3K79me2 levels. AF-9