RBPL-1, the C. elegans homolog of RBBP6, promotes meiotic homolog pairing through a conserved DWNN domain

Accurate chromosome segregation during meiosis depends on precise homolog pairing, a process driven by a series of specialized proteins that link chromosomes to cytoskeletal motors and coordinate chromosome movement for homolog recognition and alignment. Here, we demonstrate that RBPL-1, the C. elegans homolog of RBBP6, is necessary for normal meiotic progression, particularly for proper homolog pairing and associated nuclear reorganization. RBPL-1 is enriched on the autosomes in early and mid- pachytene nuclei. Depletion of RBPL-1 led to reduced levels of ZIM/HIM-8 family proteins and PLK-2 kinase, two critical mediators of homolog pairing. Notably, RBPL-1's role in homolog pairing is independent of the RING finger domain, which mediates ubiquitination, and its Zn knuckle domain, which is implicated in APA/mRNA processing. Instead, we reveal that the evolutionarily conserved yet functionally enigmatic DWNN domain is essential for RBPL-1's function. Our findings uncover a previously unrecognized regulatory mechanism governing homolog pairing during meiosis.