Component of a Polycomb group (PcG) multiprotein PRC1-like complex, a complex class required to maintain the transcriptionally repressive state of many genes, throughout development (By similarity). Required for 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). Component of a PRC1-like complex. Expression begins early in embryogenesis and continues in larval development and into adulthood of males and hermaphrodites. Viable, but has defects in the male-specific genital sensilla (simple sense organs) known as rays (PubMed:19211678). Defects in the migration and axon extension of the hermaphrodite specific neurons (HSN) during embryogenesis (PubMed:19211678). Ubiquitin-modified histone H2A is not detected in mutants (PubMed:19211678). RNAi-mediated knockdown in a lin-15 mutant background causes a multiple vulva (Muv) phenotype (PubMed:19211678).