RESUMO
Dietary proteins are crucial for oogenesis. The Target of Rapamycin (TOR) is a major nutrient sensor controlling organismal growth and fertility, but the downstream effectors of TOR signaling remain largely uncharacterized. We previously identified Drosophila Spargel/dPGC-1 as a terminal effector of the TOR-TSC pathway, and now report that Spargel connects nutrition to oogenesis. We found that Spargel is expressed predominantly in the ovaries of adult flies, and germline spargel knockdown inhibits cyst growth, ultimately leading to egg chamber degeneration and female sterility. In situ staining demonstrated nuclear localization of Spargel in the nurse cells and follicle cells of the ovariole. Furthermore, Spargel/dPGC-1 expression is influenced by dietary yeast concentration and TOR signaling, suggesting Spargel/dPGC-1 might transmit nutrient-mediated signals into ovarian growth. We propose that potentiating Spargel/dPGC-1 expression in the ovary is instrumental in nutrient-mediated regulation of oogenesis.
Assuntos
Proteínas de Drosophila/metabolismo , Oogênese/fisiologia , Ovário/metabolismo , Fator B de Elongação Transcricional Positiva/metabolismo , Animais , Proteínas Alimentares/metabolismo , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/metabolismo , Feminino , Células Germinativas/metabolismo , Nutrientes , Folículo Ovariano/metabolismo , Ovário/crescimento & desenvolvimento , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Fator B de Elongação Transcricional Positiva/fisiologia , Transdução de Sinais , Sirolimo/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Serina-Treonina Quinases TOR/fisiologiaRESUMO
Energy metabolism in vertebrates is controlled by three members of the PGC-1 (PPAR γ- coactivator 1) family, transcriptional coactivators that shape responses to physiological stimuli by interacting with the nuclear receptors and other transcription factors. Multiple evidence now supports that Spargel protein found in insects and ascidians is the ancestral form of vertebrate PGC-1's. Here, we undertook functional analysis of srl gene in Drosophila, asking about the requirement of Spargel per se during embryogenesis and its RNA binding domains. CRISPR- engineered srl gene deletion turned out to be an amorphic allele that is late embryonic/early larval lethal and Spargel protein missing its RNA binding domain (SrlΔRRM) negatively affects female fertility. Overexpression of wild-type Spargel in transgenic flies expedited the growth of egg chambers. On the other hand, oogenesis is blocked in a dominant-negative fashion in the presence of excess Spargel lacking its RRM domains. Finally, we observed aggregation of Notch proteins in egg chambers of srl mutant flies, suggesting that Spargel is involved in intracellular transport of Notch proteins. Taken together, we claim that these new mutant alleles of spargel are emerging powerful tools for revealing new biological functions for Spargel, an essential transcription coactivator in both Drosophila and mammals.
Assuntos
Proteínas de Drosophila , Drosophila melanogaster , Oogênese , Fator B de Elongação Transcricional Positiva , Animais , Feminino , Alelos , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Desenvolvimento Embrionário/genética , Oogênese/genética , Receptores Notch/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fator B de Elongação Transcricional Positiva/genética , Fator B de Elongação Transcricional Positiva/metabolismoRESUMO
Five subcluster C1 mycobacteriophages, Blackbrain, Cactojaque, Kboogie, Trinitium, and YoungMoneyMata, were isolated from soil using the host Mycobacterium smegmatis mc2155. The genome sizes range from 154,512 to 156,223 bp. The largest genome encodes 237 predicted proteins, 34 tRNAs, and 1 transfer-messenger RNA (tmRNA).
RESUMO
Four lytic mycobacteriophages, namely, SynergyX, Abinghost, Bananafish, and Delton, were isolated from soil in Washington, DC, using the bacterial host Mycobacterium smegmatis mc2155. Analysis of the genomes revealed that they belong to two subclusters of actinobacteriophage cluster B (subclusters B2 and B3) and subcluster D1 of cluster D.
RESUMO
Two temperate mycobacteriophages, Dallas and Jonghyun, were isolated from soil in Washington, DC, using the bacterial host Mycobacterium smegmatis mc2155. Analysis of the genomes revealed that Dallas and Jonghyun belong to clusters J and G, respectively. The structures of the genomes are typical of their respective clusters.