RESUMEN
Two broad gene classes are distinguished within multicellular organisms: cell type-specific genes, which confer particular cellular properties, and ubiquitous genes that support general cellular functions. However, certain so-called ubiquitous genes show functionally relevant cell type-specific repression. How such repression is achieved is poorly understood. MicroRNAs (miRNAs) are repressors, many of which are expressed with high cell type specificity. Here we show that mir-791, expressed exclusively in the CO2-sensing neurons in Caenorhabditis elegans, represses two otherwise broadly expressed genes. This repression is necessary for normal neuronal function and behavior of the animals toward CO2 miRNA-mediated repression of broadly transcribed genes is a previously unappreciated strategy for cellular specialization.
Asunto(s)
Conducta Animal , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Regulación del Desarrollo de la Expresión Génica , MicroARNs/metabolismo , Células Receptoras Sensoriales/metabolismo , Animales , Reacción de Prevención , Proteínas de Caenorhabditis elegans/genética , Dióxido de Carbono/metabolismo , MicroARNs/genéticaRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMEN
The maintenance of proteostasis is crucial for any organism to survive and reproduce in an ever-changing environment, but its efficiency declines with age1. Posttranscriptional regulators such as microRNAs control protein translation of target mRNAs with major consequences for development, physiology, and longevity2,3. Here we show that food odor stimulates organismal proteostasis and promotes longevity in Caenorhabditis elegans through mir-71-mediated inhibition of tir-1 mRNA stability in olfactory AWC neurons. Screening a collection of microRNAs that control aging3 we find that miRNA mir-71 regulates lifespan and promotes ubiquitin-dependent protein turnover, particularly in the intestine. We show that mir-71 directly inhibits the toll receptor domain protein TIR-1 in AWC olfactory neurons and that disruption of mir-71/tir-1 or loss of AWC olfactory neurons eliminates the influence of food source on proteostasis. mir-71-mediated regulation of TIR-1 controls chemotactic behavior and is regulated by odor. Thus, odor perception influences cell-type specific miRNA-target interaction to regulate organismal proteostasis and longevity. We anticipate that the proposed mechanism of food perception will stimulate further research on neuroendocrine brain-to-gut communication and may open the possibility for therapeutic interventions to improve proteostasis and organismal health via the sense of smell, with potential implication for obesity, diabetes and aging.