Trithorax-group gene homolog required for early embryogenesis (PubMed:20118203, PubMed:21423667). Required for the expression of FLC and FLC homologs and represses flowering (PubMed:21423667). Required for proper leaf growth and development (PubMed:21423667). Part of COMPASS-like complexes responsible for H3K4 trimethylation, but not for di- or mono-methylation of histone H3 'Lys-4' (PubMed:21423667). Binds to target loci chromatin, increasing H3K4 trimethylation and causing activation of the gene (PubMed:21423667). Involved in the transition from transcription initiation to transcription elongation (PubMed:23284292). Part of a complex composed of TRO, RBL and WDR5A. Interacts with RBL, but not with WDR5A or WDR5B. This complex is formed during both vegetative and reproductive development. Ubiquitous. Highest expression in pollen and seeds. Expressed in the embryo and the suspensor cells. Detected in cotyledons, roots, leaf hydathodes, sepals, anthers and pollen grains (PubMed:20118203). Strongly expressed in root tips, shoot apices, vascular tissues, developing embryos and endosperms (PubMed:21423667). Expressed during embryo development. Embryo lethality when homozygous (PubMed:20118203, PubMed:21423667). Eearly flowering (PubMed:23284292). Slightly lower ATX1 occupancy at the 5'-end regions of the target genes (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). Named TRAUCO (TRO) in honor of the fertility mythology from the Chiloe island in southern Chile.