Environmental and simulation facility conditions can modulate a behavioral-driven altered gravity response of Drosophila imagoes transcriptome

Genome-wide transcriptional profiling shows that reducing gravity levels in the International Space Station (ISS) causes important alterations in Drosophila gene expression. However, simulation experiments on ground, without space constraints, show weaker effects than space environment. A global and integrative analysis using the gene expression dynamics inspector (GEDI) self-organizing maps, reveals a subtle response of the transcriptome using different populations and microgravity and hypergravity simulation devices. These results suggest that, in addition to behavioural responses that can be detected also at the gene expression level, the transcriptome is finely tuned to normal gravity. The alteration of this constant parameter on Earth can have effects on gene expression that depends both on the environmental conditions and the ground based facility used to compensate the gravity vector. Alternative and commons effects of mechanical facilities, like the Random Positioning Machine and a centrifuge, and strong magnetic field ones, like a cryogenically cooled superconductive magnet, are discussed. We compare the effects over the gene expression profile of different sex/age Drosophila imagoes in 3-4 days-long experiments under altered gravity conditions into three GBF (Ground Based Facilities for micro/hyper- gravity simulation) using whole genome microarray platforms. Descriptions of different GBFs (treatments): LDC means Large Diameter Centrifuge. Samples can be placed under three conditions: inside LDC (at certain g level), at the LDC rotational control and at external 1g control (outside the LDC). RPM means Random Positioning Machine. Samples can be placed under two conditions: inside RPM (at nearly 0g, Microgravity level) and at external 1g control (outside the RPM). At the magnet, means INSIDE the Magnetic levitator (another GBF). Samples can be placed under four conditions: inside Magnet 0g* (at microgravity with magnetic field), inside Magnet at 1g* (internal control with magnetic field) or inside the magnet 2g* (at hypergravity with magnetic field) and at external 1g control (outside the magnet)