Male Differentiation in the Marine Copepod Oithona nana Reveals the Development of a New Nervous Ganglion and Lin12-Notch-Repeat Protein-Associated Proteolysis

Copepods are among the most numerous animals, and they play an essential role in marine trophic web biogeochemical cycles. The genus Oithona is described as having highest density of copepods. male paradox describes activity states males, which obliged to alternate between immobile mobile phases for ambush feeding mate searching, respectively, while female less feeds less. To characterize molecular basis this sexual dimorphism, we combined immunofluorescence, genomics, transcriptomics, protein–protein interaction approaches revealed presence a male-specific nervous ganglion. Transcriptomic analysis showed enrichment system development-related transcripts. Twenty-seven Lin12-Notch Repeat domain-containing protein coding genes (LDPGs) 75 LDPGs identified genome were specifically expressed males. Furthermore, some coded proteins with predicted proteolytic activity, proteases-associated transcripts enrichment. Using yeast double–hybrid assays, constructed network involving two LDPs proteases, extracellular matrix proteins, neurogenesis-related proteins. We also hypothesized possible roles development lateral ganglia through helping lysis, neurites growth guidance, synapses genesis.