InterPro domain: IPR007149

In budding yeasts, Leo1 is part of the Paf1 complex, an RNA polymerase II-associated protein complex containing Paf1, Cdc73, Ctr9, Rtf1 and Leo1. Paf1 complex is involved in histone modifications, transcription elongation and other gene expression processes that include transcript site selection [ 1 ].

This entry also includes Leo1 homologues from animals and plants. Human Leo1, also known as RDL, is a component of the human Paf1 complex (Paf1C), which consists of Paf1, Cdc73, Ctr9, Rtf1, Leo1 and Wdr61 (Ski8). As in yeast, the human Paf1C has a central role in co-transcriptional histone modifications [ 2 ]. Human Leo1 promotes senescence of 2BS fibroblasts [ 2 ].

Arabidopsis Paf1C related proteins such as VIP4 (Leo1), VIP5 (Rtf1), ELF7 (Paf1), ELF8 (Ctr9) and ATXR7 (Set1) are required for the induction of seed dormancy. They control both germination and flowering time [ 3 ].

1. The human PAF1 complex acts in chromatin transcription elongation both independently and cooperatively with SII/TFIIS. Cell 140, 491-503
2. Expression of the Leo1-like domain of replicative senescence down-regulated Leo1-like (RDL) protein promotes senescence of 2BS fibroblasts. FASEB J. 19, 521-32
3. Identification of the Arabidopsis REDUCED DORMANCY 2 gene uncovers a role for the polymerase associated factor 1 complex in seed dormancy. PLoS ONE 6, e22241