RESUMO
Obesity is mainly due to excessive food intake. IRX3 and IRX5 have been suggested as determinants of obesity in connection with the intronic variants of FTO, but how these genes contribute to obesity via changes in food intake remains unclear. Here, we show that mice doubly heterozygous for Irx3 and Irx5 mutations exhibit lower food intake with enhanced hypothalamic leptin response. By lineage tracing and single-cell RNA sequencing using the Ins2-Cre system, we identify a previously unreported radial glia-like neural stem cell population with high Irx3 and Irx5 expression in early postnatal hypothalamus and demonstrate that reduced dosage of Irx3 and Irx5 promotes neurogenesis in postnatal hypothalamus leading to elevated numbers of leptin-sensing arcuate neurons. Furthermore, we find that mice with deletion of Irx3 in these cells also exhibit a similar food intake and hypothalamic phenotype. Our results illustrate that Irx3 and Irx5 play a regulatory role in hypothalamic postnatal neurogenesis and leptin response.
Assuntos
Proteínas de Homeodomínio/genética , Hipotálamo/metabolismo , Insulina/genética , Leptina/metabolismo , Neurogênese/genética , Fatores de Transcrição/genética , Animais , Comportamento Alimentar , Imunofluorescência , Regulação da Expressão Gênica , Estudos de Associação Genética , Proteínas de Homeodomínio/metabolismo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Células-Tronco Neurais , Neurônios/metabolismo , Fenótipo , RNA Citoplasmático Pequeno/genética , Fatores de Transcrição/metabolismoRESUMO
Discovering target and off-target effects of specific compounds is critical to drug discovery and development. We generated a compendium of "chemical-genetic interaction" profiles by testing the collection of viable yeast haploid deletion mutants for hypersensitivity to 82 compounds and natural product extracts. To cluster compounds with a similar mode-of-action and to reveal insights into the cellular pathways and proteins affected, we applied both a hierarchical clustering and a factorgram method, which allows a gene or compound to be associated with more than one group. In particular, tamoxifen, a breast cancer therapeutic, was found to disrupt calcium homeostasis and phosphatidylserine (PS) was recognized as a target for papuamide B, a cytotoxic lipopeptide with anti-HIV activity. Further, the profile of crude extracts resembled that of its constituent purified natural product, enabling detailed classification of extract activity prior to purification. This compendium should serve as a valuable key for interpreting cellular effects of novel compounds with similar activities.
Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Resistência a Medicamentos/genética , Perfilação da Expressão Gênica/métodos , Preparações Farmacêuticas/metabolismo , Leveduras/efeitos dos fármacos , Leveduras/genética , Antineoplásicos Hormonais/farmacologia , Antivirais/farmacologia , Análise por Conglomerados , Depsipeptídeos/farmacologia , Proteínas Fúngicas/efeitos dos fármacos , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Estrutura Molecular , Mutação/efeitos dos fármacos , Mutação/genética , Preparações Farmacêuticas/química , Preparações Farmacêuticas/classificação , Fosfatidilserinas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Tamoxifeno/farmacologia , Leveduras/metabolismoRESUMO
Candida albicans is the primary fungal pathogen of humans. Despite the need for novel drugs to combat fungal infections [Sobel, J.D. (2000) Clin Infectious Dis 30: 652], antifungal drug discovery is currently limited by both the availability of suitable drug targets and assays to screen corresponding targets. A functional genomics approach based on the diploid C. albicans genome sequence, termed GRACETM (gene replacement and conditional expression), was used to assess gene essentiality through a combination of gene replacement and conditional gene expression. In a systematic application of this approach, we identify 567 essential genes in C. albicans. Interestingly, evaluating the conditional phenotype of all identifiable C. albicans homologues of the Saccharomyces cerevisiae essential gene set [Giaever, G., Chu, A.M., Ni, L., Connelly, C., Riles, L., Veronneau, S., et al. (2002) Nature 418: 387-391] by GRACE revealed only 61% to be essential in C. albicans, emphasizing the importance of performing such studies directly within the pathogen. Construction of this conditional mutant strain collection facilitates large-scale examination of terminal phenotypes of essential genes. This information enables preferred drug targets to be selected from the C. albicans essential gene set by phenotypic information derived both in vitro, such as cidal versus static terminal phenotypes, as well as in vivo through virulence studies using conditional strains in an animal model of infection. In addition, the combination of phenotypic and bioinformatic analyses further improves drug target selection from the C. albicans essential gene set, and their respective conditional mutant strains may be directly used as sensitive whole-cell assays for drug screening.