Royal jelly attenuates metabolic defects in a Drosophila mutant with elevated TORC1 activity

ABSTRACTTarget of rapamycin complex 1 (TORC1) is a master regulator of cell metabolism, and its dysregulation has been linked to an array of pathologies, including cancer and age-related diseases. Nprl3, a component of GTPase-activating protein towards Rags complex 1 (GATOR1), inhibits TORC1 activity under nutrient scarcity status. The nprl3 mutant exhibits some metabolic defects due to hyper TORC1 activity in Drosophila. Royal jelly (RJ) is a honeybee-secreted product and plays an essential role in caste differentiation that requires TORC1 activity. RJ is also used as a health-benefit food for its potential roles on antioxidant and anti-aging. In this study, nprl3-mutant flies were used to measure the effect of RJ on metabolic modulation. Interestingly, RJ feeding significantly increased survival and decreased TORC1 activity in the nprl3 mutant. RJ feeding also ameliorated the abnormal reactive oxygen species (ROS) levels and energy status in the nprl3 mutant. The proteins in RJ were characterized to be the essential components in increasing nprl3 mutant viability. These findings suggest that RJ modulates some metabolic defects associated with elevated TORC1 activity and that the nprl3-mutant fly might be a useful tool for investigating the bioactive components of RJ in vivo.

Abnormal Social Interactions in a Drosophila Mutant of an Autism Candidate Gene: Neuroligin 3

Social interactions are typically impaired in neuropsychiatric disorders such as autism, for which the genetic underpinnings are very complex. Social interactions can be modeled by analysis of behaviors, including social spacing, sociability, and aggression, in simpler organisms such as Drosophila melanogaster. Here, we examined the effects of mutants of the autism-related gene neuroligin 3 (nlg3) on fly social and non-social behaviors. Startled-induced negative geotaxis is affected by a loss of function nlg3 mutation. Social space and aggression are also altered in a sex- and social-experience-specific manner in nlg3 mutant flies. In light of the conserved roles that neuroligins play in social behavior, our results offer insight into the regulation of social behavior in other organisms, including humans.

Arabidopsis RNA processing factor SERRATE regulates the transcription of intronless genes

Intron splicing increases proteome complexity, promotes RNA stability, and enhances transcription. However, introns and the concomitant need for splicing extend the time required for gene expression and can cause an undesirable delay in the activation of genes. Here, we show that the plant microRNA processing factor SERRATE (SE) plays an unexpected and pivotal role in the regulation of intronless genes. Arabidopsis SE associated with more than 1000, mainly intronless, genes in a transcription-dependent manner. Chromatin-bound SE liaised with paused and elongating polymerase II complexes and promoted their association with intronless target genes. Our results indicate that stress-responsive genes contain no or few introns, which negatively affects their expression strength, but that some genes circumvent this limitation via a novel SE-dependent transcriptional activation mechanism. Transcriptome analysis of a Drosophila mutant defective in ARS2, the metazoan homologue of SE, suggests that SE/ARS2 function in regulating intronless genes might be conserved across kingdoms.

Toxicology and cytogenetic analysis of a Drosophila melanogaster mutant resistant to Imidacloprid and DDT

Resistance to all major insecticide classes has developed in numerous and diverse insect field populations. Imidacloprid, the worldwide most used neonicotinoid, has been extensively applied during the last decade for the control of different insect pests. Lately, cases of sporadic resistance also to neonicotinoids, including Imidacloprid, have been reported. Drosophila melanogaster is one of the most popular model organisms in biology and, although not a pest species, a promising model system for insecticide resistance research. In this study, we present a toxicological and karyotypic analysis of a Drosophila mutant (MiT[w-]3R2) resistant to Imidacloprid and cross-resistant to DDT. Karyotype analysis of polytene chromosome of MiT[w-]3R2 flies did not identify any apparent structural change of the polytene chromosome linked with the resistance phenotype.