Research activity
Sleep is a mysterious activity. All animals that have been tested so far, from the simplest invertebrates to the highest mammals, have shown to possess – and to require – the fundamental characteristics of sleep, independently of the size or the complexity of their nervous systems. In all animals sleep is a vital necessity, as chronic sleep deprivation leads to a still unexplained death. Most animals sleep for a considerable fraction of their life and also the molecular basis of sleep regulation seem to be strongly conserved as most species respond in the same way to many hypnotic drugs or wake-stimulants. This remarkable conservation across evolution suggests that the core function of sleep has to be sought at the basic cell biological level of neuronal function, namely that sleep is an intrinsic requirement of any neuronal network and, possibly, every neuron (or even cell?). Yet, so far, most of the efforts in investigating the function of sleep have been focused on electrophysiological analysis of the sleeping brain in a very descriptive fashion. We know a great deal about the EEG (electroencephalogram) correlates of sleep and wakefulness but this knowledge could not, by itself, shed a deep light on the function of sleep.
My goal is to tackle the problem from a different perspective, using a combination of genetics, molecular biology and bioinformatics.
Sleep,
circadian,
behaviour,
learning and memory,
3D printing,
TALENRepresentative publications
- Gilestro GF. Video tracking and analysis of sleep in Drosophila melanogaster. Nat Protoc. 2012 Apr 26;7(5):995-1007. PMID: 22538850.
Abstract
In the past decade, Drosophila has emerged as an ideal model organism for studying the genetic components of sleep as well as its regulation and functions. In fruit flies, sleep can be conveniently estimated by measuring the locomotor activity of the flies using techniques and instruments adapted from the field of circadian behavior. However, proper analysis of sleep requires degrees of spatial and temporal resolution higher than is needed by circadian scientists, as well as different algorithms and software for data analysis. Here I describe how to perform sleep experiments in flies using techniques and software (pySolo and pySolo-Video) previously developed in my laboratory. I focus on computer-assisted video tracking to monitor fly activity. I explain how to plan a sleep analysis experiment that covers the basic aspects of sleep, how to prepare the necessary equipment and how to analyze the data. By using this protocol, a typical sleep analysis experiment can be completed in 5-7 d.
- Gilestro GF, Cirelli C. pySolo: a complete suite for sleep analysis in Drosophila. Bioinformatics. 2009 Jun 1;25(11):1466-7. PMID: 19369499.
Abstract
SUMMARY: pySolo is a multiplatform software for analysis of sleep and locomotor activity in Drosophila melanogaster. pySolo provides a user-friendly graphic interface and it has been developed with the specific aim of being accessible, portable, fast and easily expandable through an intuitive plug-in structure. Support for development of additional plug-ins is provided through a community website. AVAILABILITY: Software and documentation are located at (http://www.pysolo.net). pySolo is a free software released under the GNU General Public License.
- Gilestro GF, Tononi G, Cirelli C. Widespread changes in synaptic markers as a function of sleep and wakefulness in Drosophila. Science. 2009 Apr 3;324(5923):109-12. PMID: 19342593.
Abstract
Sleep is universal, strictly regulated, and necessary for cognition. Why this is so remains a mystery, although recent work suggests that sleep, memory, and plasticity are linked. However, little is known about how wakefulness and sleep affect synapses. Using Western blots and confocal microscopy in Drosophila, we found that protein levels of key components of central synapses were high after waking and low after sleep. These changes were related to behavioral state rather than time of day and occurred in all major areas of the Drosophila brain. The decrease of synaptic markers during sleep was progressive, and sleep was necessary for their decline. Thus, sleep may be involved in maintaining synaptic homeostasis altered by waking activities.
- Gilestro GF. Redundant mechanisms for regulation of midline crossing in Drosophila. PLoS One. 2008;3(11):e3798. PMID: 19030109.
Abstract
During development, all neurons have to decide on whether to cross the longitudinal midline to project on the contralateral side of the body. In vertebrates and invertebrates regulation of crossing is achieved by interfering with Robo signalling either through sorting and degradation of the receptor, in flies, or through silencing of its repulsive activity, in vertebrates. Here I show that in Drosophila a second mechanism of regulation exists that is independent from sorting. Using in vitro and in vivo assays I mapped the region of Robo that is sufficient and required for its interaction with Comm, its sorting receptor. By modifying that region, I generated new forms of Robo that are insensitive to Comm sorting in vitro and in vivo, yet still able to normally translate repulsive activity in vivo. Using gene targeting by homologous recombination I created new conditional alleles of robo that are sorting defective (robo(SD)). Surprisingly, expression of these modified proteins results in phenotypically normal flies, unveiling a sorting independent mechanism of regulation.
