RESUMO
In Drosophila, ~150 neurons expressing molecular clock proteins regulate circadian behavior. Sixteen of these neurons secrete the neuropeptide Pdf and have been called 'master pacemakers' because they are essential for circadian rhythms. A subset of Pdf+ neurons (the morning oscillator) regulates morning activity and communicates with other non-Pdf+ neurons, including a subset called the evening oscillator. It has been assumed that the molecular clock in Pdf+ neurons is required for these functions. To test this, we developed and validated Gal4-UAS based CRISPR tools for cell-specific disruption of key molecular clock components, period and timeless. While loss of the molecular clock in both the morning and evening oscillators eliminates circadian locomotor activity, the molecular clock in either oscillator alone is sufficient to rescue circadian locomotor activity in the absence of the other. This suggests that clock neurons do not act in a hierarchy but as a distributed network to regulate circadian activity.
Assuntos
Relógios Circadianos/genética , Ritmo Circadiano/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Neurônios/metabolismo , Neuropeptídeos/genética , Proteínas Circadianas Period/genética , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Encéfalo/efeitos da radiação , Sistemas CRISPR-Cas , Comunicação Celular , Linhagem da Célula/genética , Relógios Circadianos/efeitos dos fármacos , Ritmo Circadiano/efeitos dos fármacos , Escuridão , Proteínas de Drosophila/deficiência , Drosophila melanogaster/metabolismo , Drosophila melanogaster/efeitos da radiação , Retroalimentação Fisiológica , Edição de Genes , Regulação da Expressão Gênica , Transdução de Sinal Luminoso/genética , Locomoção/genética , Locomoção/efeitos da radiação , Rede Nervosa/metabolismo , Rede Nervosa/efeitos da radiação , Neurônios/citologia , Neurônios/efeitos da radiação , Neuropeptídeos/deficiência , Proteínas Circadianas Period/deficiência , Fatores de Transcrição/deficiência , Fatores de Transcrição/genéticaRESUMO
Fragile X syndrome, the most common known monogenic cause of autism, results from the loss of FMR1, a conserved, ubiquitously expressed RNA-binding protein. Recent evidence suggests that Fragile X syndrome and other types of autism are associated with immune system defects. We found that Drosophila melanogaster Fmr1 mutants exhibit increased sensitivity to bacterial infection and decreased phagocytosis of bacteria by systemic immune cells. Using tissue-specific RNAi-mediated knockdown, we showed that Fmr1 plays a cell-autonomous role in the phagocytosis of bacteria. Fmr1 mutants also exhibit delays in two processes that require phagocytosis by glial cells, the immune cells in the brain: neuronal clearance after injury in adults and the development of the mushroom body, a brain structure required for learning and memory. Delayed neuronal clearance is associated with reduced recruitment of activated glia to the site of injury. These results suggest a previously unrecognized role for Fmr1 in regulating the activation of phagocytic immune cells both in the body and the brain.