E3 ubiquitin-protein ligase playing a central role in histone code and gene regulation (By similarity). Involved in ubiquitination of histone H2A (PubMed:19211678). Plays a role in the formation of the male-specific genital sensilla (simple sense organs) known as rays (PubMed:19211678). Required for normal migration of the hermaphrodite specific neurons (HSN) and for extension of some neuronal processes (PubMed:19211678). Represses vulval fates in hypodermal cells that do not normally contribute to vulval development (PubMed:19211678). S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Component of chromatin-associated Polycomb (PcG) complexes (By similarity). Component of a PRC1-like complex (By similarity). RNAi-mediated knockdown in a lin-15 mutant background causes a multiple vulva (Muv) phenotype.