Component of the SET1 complex that specifically di- and trimethylates 'Lys-4' of histone H3. Essential for Set1 association with chromatin and trimethylation of histone H3 at 'Lys-4' at transcription puffs. Additionally, is critical for general chromosomal association of Set1. Component of the SET1 complex, composed at least of the catalytic subunit Set1, wds/WDR5, Wdr82, Rbbp5, ash2, Cfp1/CXXC1, hcf and Dpy-30L1.