RESUMEN
The Hippo pathway is crucial for not only normal growth and apoptosis but also cell fate specification during development. What controls Hippo pathway activity during cell fate specification is incompletely understood. In this article, we identify the insulator protein BEAF-32 as a regulator of Hippo pathway activity in Drosophila photoreceptor differentiation. Though morphologically uniform, the fly eye is composed of two subtypes of R8 photoreceptor neurons defined by expression of light-detecting Rhodopsin proteins. In one R8 subtype, active Hippo signaling induces Rhodopsin 6 (Rh6) and represses Rhodopsin 5 (Rh5), whereas in the other subtype, inactive Hippo signaling induces Rh5 and represses Rh6. The activity state of the Hippo pathway in R8 cells is determined by the expression of warts, a core pathway kinase, which interacts with the growth regulator melted in a double-negative feedback loop. We show that BEAF-32 is required for expression of warts and repression of melted Furthermore, BEAF-32 plays a second role downstream of Warts to induce Rh6 and prevent Rh5 fate. BEAF-32 is dispensable for Warts feedback, indicating that BEAF-32 differentially regulates warts and Rhodopsins. Loss of BEAF-32 does not noticeably impair the functions of the Hippo pathway in eye growth regulation. Our study identifies a context-specific regulator of Hippo pathway activity in post-mitotic neuronal fate, and reveals a developmentally specific role for a broadly expressed insulator protein.
Asunto(s)
Diferenciación Celular , Proteínas de Unión al ADN/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/citología , Drosophila melanogaster/metabolismo , Proteínas del Ojo/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neuronas/citología , Neuronas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , Animales , Retroalimentación Fisiológica , Células Fotorreceptoras de Invertebrados/metabolismo , Unión Proteica , Rodopsina/metabolismoRESUMEN
OBJECTIVE: Heredity has a remarkable effect on obesity in an obesogenic environment. Despite the numerous genetic variants that contribute to obesity-related traits, none has been identified in Chinese children. This study aimed to identify novel variants associated with childhood obesity in China. METHODS: Promising single-nucleotide variants were obtained using whole-exome sequencing from 76 children who had obesity and 74 children with normal weight, and their associations with obesity-related traits in an additional 6,334-child cohort were investigated. The effects of the genome-wide significant (P < 5E-8) variants on the expression of the implicated genes in blood and adipose tissue were then depicted using transcriptome sequencing. RESULTS: Two coding variants associated with obesity with genome-wide significance were identified: rs1059491 (P = 2.57E-28) in SULT1A2 and rs189326455 (P = 8.98E-12) in MAP3K21. In addition, rs1059491 was also significantly associated with several obesity traits. Transcriptome sequencing demonstrated that rs1059491 and rs189326455 were expression quantitative trait loci relevant to the expression levels of several obesity-related genes, such as SULT1A2, ATXN2L, TUFM, and MAP3K21. CONCLUSIONS: This work identified two coding variants that were significantly associated with pediatric adiposity and were expression quantitative trait loci for obesity-related genes. This study provides new insights into the pathophysiology of Chinese childhood obesity.