LÉOPOLD , Pierre

Target of rapamycin (TOR) and insulin receptor pathways regulate growth in metazoans. A recent study reveals a novel role for these pathways in controlling the timing of neuronal differentiation during Drosophila development, thus allowing a tight coordination between growth and differentiation programs.

The Drosophila miRNA-encoding gene bantam controls cell and tissue growth. A new study now reveals that a large part of its effects on growth could come from its inhibition of the production of the molting hormone ecdysone.

The molecule Hedgehog is well known as an organizer of tissue morphogenesis. A recent report now demonstrates that it also plays the role of a gut hormone, orchestrating the nutrient response during fly development.

The Drosophila miRNA-encoding gene bantam controls cell and tissue growth. A new study now reveals that a large part of its effects on growth could come from its inhibition of the production of the molting hormone ecdysone.

International audience

Lipids provide an essential source of metabolites and energy in normal development as well as during periods of food deprivation. A recent study in Drosophila (Gutierrez et al., 2007) reveals a novel role in regulating lipid metabolism for specialized cells called oenocytes that present striking functional similarities to mammalian hepatocytes.

DOR, a nuclear receptor co-activator conserved from flies to humans, provides a molecular connection between ecdysone and insulin signaling, two important pathways controlling developmental timing and growth, respectively.

In multicellular organisms, insulin/IGF signaling (IIS) plays a central role in matching energy needs with uptake and storage, participating in functions as diverse as metabolic homeostasis, growth, reproduction and ageing. In mammals, this pleiotropy of action relies in part on a dichotomy of action of insulin, IGF-I and their respective...

International audience

International audience

How steroid hormones shape animal growth remains poorly understood. In Drosophila, the main steroid hormone, ecdysone, limits systemic growth during juvenile development. Here we show that ecdysone controls animal growth rate by specifically acting on the fat body, an organ that retains endocrine and storage functions of the vertebrate liver...

Tissue growth during animal development is tightly controlled so that the organism can develop harmoniously. The salvador (sav) gene, which encodes a scaffold protein, has been shown to restrict cell number by coordinating cell-cycle exit and apoptosis during Drosophila development. Here we identify Hippo (Hpo), the Drosophila orthologue of the...

Growth is a complex process that is intimately linked to the developmental program to form adults with proper size and proportions. Genetics is an important determinant of growth, as exemplified by the role of local diffusible molecules setting up organ proportions. In addition, organisms use adaptive responses allowing modulating the size of...

Developing organisms use fine-tuning mechanisms to adjust body growth to ever-changing nutritional conditions. In Drosophila, the secretory activity of insulin-producing cells (IPCs) is central to couple systemic growth with amino acids availability. Here, we identify a subpopulation of inhibitory neurons contacting the IPCs (IPC-connecting...

In many metazoans, final adult size depends on the growth rate and the duration of the growth period, two parameters influenced by nutritional cues. We demonstrate that, in Drosophila, nutrition modifies the timing of development by acting on the prothoracic gland (PG), which secretes the molting hormone ecdysone. When activity of the Target of...

International audience

International audience

Insulin-like peptides (ILPs) couple growth, metabolism, longevity, and fertility with changes in nutritional availability. In Drosophila, several ILPs called Dilps are produced by the brain insulin-producing cells (IPCs), from which they are released into the hemolymph and act systemically. We show here that in response to nutrient deprivation,...

Little is known about how organ growth is monitored and coordinated with the developmental timing in complex organisms. In insects, impairment of larval tissue growth delays growth and morphogenesis, revealing a coupling mechanism. We carried out a genetic screen in Drosophila to identify molecules expressed by growing tissues participating in...

International audience

Basal autophagy is as a compressive catabolic mechanism engaged in the breakdown of damaged macromolecules and organelles leading to the recycling of elementary nutrients. Thought essential to cellular refreshing, little is known about the origin of a constitutional rate of basal autophagy. Here, we found that loss of Drosophila vacuolar...

The onset of sexual maturation is the result of a hormonal cascade peaking with the production of steroid hormones. In animals undergoing a program of determinate growth, sexual maturation also coincides with the attainment of adult size. The exact signals that time the onset of maturation and the mechanisms coupling growth and maturation...

Eukaryotic initiation factor 4E (eIF4E) controls a crucial step of translation initiation and is critical for cell growth . Biochemical studies have shown that it undergoes a regulated phosphorylation by the MAP-kinase signal-integrating kinases Mnk1 and Mnk2 . Although the role of eIF4E phosphorylation in mammalian cells has remained elusive ,...

International audience

Multicellular organisms grow through both proliferation and growth of their individual cells. We have conducted a P-element-based misexpression screen for genes whose upregulation alters wing disc growth during development. One particular group of four P elements, all inserted at cytological location 61C7-8, exhibited specific overgrowth upon...