St. Ange, J. | bioRxiv Science

bioRxiv2024

Single-Nucleus Neuronal Transcriptional Profiling of Male C. elegans Uncovers Regulators of Sex-Specific and Sex-Shared Behaviors

Sexual differentiation of the nervous system drives profound neurobiological and behavioral differences between the sexes across various organisms, including Caenorhabditis elegans. Using single-nucleus RNA sequencing, we profiled and compared adult male and hermaphrodite C. elegans neurons, generating an atlas of adult male-specific and sex-shared neurons. We expanded the molecular map of male-specific neurons, and identified highly dimorphic expression of GPCRs, neuropeptides, and ion channels. Our data demonstrate sex-shared neurons exhibit substantial heterogeneity between the sexes, while sex-specific neurons repurpose conserved molecular pathways to regulate dimorphic behaviors. We show that the PHD neurons display remarkable similarity to sex-shared AWA neurons, suggesting partial repurposing of conserved pathways, and that they and the GPCR SRT-18 may play a role in pheromone sensing. We further demonstrate that the ubiquitously expressed MAPK phosphatase vhp-1 regulates both sex-specific and sex-shared behaviors. Our data provide a rich resource for discovering sex-specific transcriptomic differences and the molecular basis of sex-specific behaviors.

neuroscience↗

bioRxiv2024

Adult Single-nucleus Neuronal Transcriptomes of Insulin Signaling Mutants Reveal Regulators of Behavior and Learning

The insulin/insulin-like signaling (IIS) pathway regulates many of C. elegans adult functions, including learning and memory1. While whole-worm and tissue-specific transcriptomic analyses have identified IIS targets2,3, a higher-resolution single-cell approach is required to identify changes that confer neuron-specific improvements in the long-lived insulin receptor mutant, daf-2. To understand how behaviors that are controlled by a small number of neurons change in daf-2 mutants, we used the deep resolution of single-nucleus RNA sequencing to define each neuron types transcriptome in adult wild-type and daf-2 mutants. First, we found surprising differences between wild-type L4 larval neurons and young adult neurons in chemoreceptor expression, synaptic genes, and learning and memory genes. These Day 1 adult neuron transcriptomes allowed us to identify adult AWC-specific regulators of chemosensory function and to predict neuron-to-neuron peptide/receptor pairs. We then identified gene expression changes that correlate with daf-2s improved cognitive functions, particularly in the AWC sensory neuron that controls learning and associative memory4, and used behavioral assays to test their roles in cognitive function. Combining deep single-neuron transcriptomics, genetic manipulation, and behavioral analyses enabled us to identify genes that may function in a single adult neuron to control behavior, including conserved genes that function in learning and memory. One-Sentence SummarySingle-nucleus sequencing of adult wild-type and daf-2 C. elegans neurons reveals functionally relevant transcriptional changes, including regulators of chemosensation, learning, and memory.

neuroscience↗