Copulation in C. elegans males requires a nuclear hormone receptor

• Published in: Developmental biology 2008-10, Vol.322 (1), p.11-20
• Main Authors: Shan, Ge, Walthall, W.W.
• Format: Article
• Language: English
• Subjects: Alternative splicing; Alternative Splicing - genetics; Animals; Animals, Genetically Modified; C. elegans; Caenorhabditis elegans; Caenorhabditis elegans - genetics; Caenorhabditis elegans - physiology; Caenorhabditis elegans Proteins - genetics; Caenorhabditis elegans Proteins - physiology; Copulation - physiology; Gene Expression Regulation, Developmental; Genes, Reporter; Locomotion - genetics; Male; Male mating; Molecular Sequence Data; Nuclear hormone receptor; Protein Isoforms - genetics; Protein Isoforms - physiology; Receptors, Cell Surface - genetics; Receptors, Cell Surface - physiology; Receptors, Cytoplasmic and Nuclear - genetics; Receptors, Cytoplasmic and Nuclear - physiology; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - genetics; RNA Interference; Sex Characteristics; Sexual Behavior, Animal - physiology; Sexual dimorphism; Spicule protractor and retractor muscles
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/j.ydbio.2008.06.034

In Caenorhabditis elegans, uncoordinated (unc)-55 encodes a nuclear hormone receptor that is necessary for coordinated movement and male mating. An unc-55 reporter gene revealed a sexually dimorphic pattern: early in post-embryonic motor neurons in both sexes; and later in a subset of male-specific cells that included an interneuron and eight muscle cells. A behavioral analysis coupled with RNA interference (RNAi) revealed that males require UNC-55 to execute copulatory motor programs. Two mRNA isoforms ( unc-55a and unc-55b) were detected throughout post-embryonic development in males, whereas only one, unc-55a, was detected in hermaphrodites. In unc-55 mutant males isoform a rescued the locomotion and mating defect, whereas isoform b rescued the mating defect only. Isoform b represents the first report of male-specific splicing in C. elegans. In addition, isoform b extended the number of days that transgenic unc-55 mutant males mated when compared to males rescued with isoform a, suggesting an anabolic role for the nuclear hormone receptor. The male-specific expression and splicing is part of a regulatory hierarchy that includes two key genes, male abnormal (mab)-5 and mab-9, required for the generation and differentiation of male-specific cells. We suggest that UNC-55 acts as an interface between genes involved in male tail pattern formation and those responsible for function.