Component of the PAF1 complex (PAF1C) which is involved in histone modifications such as methylation on histone H3 'Lys-4' (H3K4me3) (PubMed:20363855). Involved in regulation of flowering time. Required for the expression of the flowering repressor and MADS box gene FLC (PubMed:12207655). Involved in the control of seed dormancy and germination (PubMed:21799800). Component of the nuclear PAF1 complex (PAF1C), which consists of VIP2/ELF7/PAF1, VIP3/SKI8/WDR61, VIP4/LEO1, VIP5/RTF1, VIP6/ELF8/CTR9 and CDC73 (PubMed:20363855). Interacts with VIP3 and VIP6 (PubMed:15472079). A number of isoforms are produced. According to EST sequences. Expressed in roots, shoot apices, stems, cauline leaves, inflorescence apices and flowers. Early flowering, defects in floral morphology in whorls 1-3, but fully fertile flowers (PubMed:12207655). Reduced seed dormancy and increased germination rate of freshly harvested seeds (PubMed:21799800). Belongs to the LEO1 family.