Forms multiple COMPASS-like complexes involved in histone methylation by interacting with different histone H3 'Lys-4' methyltransferases such as ATX1, SDG14 or SDG16 (PubMed:21423667). Binds to target loci chromatin, increasing H3K4 trimethylation and causing activation of the gene (PubMed:19567704). Up-regulates FLC and MAF4 expression to delay flowering (PubMed:19567704). Present at the promoters and at the transcription start sites (TSS) regions of WRKY70 and LTP7; this occupancy is ATX1-dependent (PubMed:23284292). Involved in the transition from transcription initiation to transcription elongation (PubMed:23284292). Part of a complex composed of TRO, RBL and WDR5A (PubMed:21423667). This complex is formed during both vegetative and reproductive development (PubMed:21423667). Interacts with SDG14, SDG16, RBL, but not with TRO (PubMed:21423667). Interacts with ATX1 and K4-methylated H3 tails (PubMed:19567704). Strongly expressed in developing embryos and endosperms (PubMed:21423667). Expressed in shoot and root apical regions, and in vasculature (PubMed:19567704). Eearly flowering (PubMed:23284292). Decreased TATA-binding protein (TBP) levels lower Ser5P Pol II levels near the transcription start sites (TSSs) of target genes and of Pol II at the genes 3'-ends thus affecting the transition from transcription initiation to transcription elongation (PubMed:23284292). Significantly reduced trimethylated 'Lys-4' of histone H3 (H3K4me3) levels at the 5'-ends of WRKY70 and LTP7 genes leading to reduced transcript accumulation (PubMed:23284292).