Project description:In Drosophila, fibrillar flight muscles (IFMs) enable flight, while tubular muscles mediate other body movements. Here, we use RNA-sequencing and isoform-specific reporters to show that spalt major (salm) determines fibrillar muscle physiology by regulating transcription and alternative splicing of a large set of sarcomeric proteins. We identify the RNA binding protein Arrest (Aret, Bruno) as downstream of salm. Aret shuttles between cytoplasm and nuclei, and is essential for myofibril maturation and sarcomere growth of IFMs. Molecularly, Aret regulates IFM-specific transcription and splicing of various sarcomeric targets, including Stretchin and wupA (TnI), and thus maintains muscle fiber integrity. As Aret and its sarcomeric targets are evolutionarily conserved, similar principles may regulate mammalian muscle morphogenesis. 9 samples from Drosophila melanogaster were analyzed in duplicate: control dissected wildtype flight muscle at 30h APF, 72h APF and 0 day adult, jump muscle and whole leg from 1d adult and RNAi/mutant conditions for salm (1d flight muscle) and aret (30h, 72h and 1d flight muscle)
Project description:Our study focuses on understanding the early transcriptional changes taking place during the divergence of the adult muscle precursors that give rise to indirect flight muscles and direct flight muscles in Drosophila. We analyzed the heterogenous cell population of the adult muscle precursors by scRNA-seq and build an integrated single-cell reference atlas. We addressed the differences among muscle-type and different cell state during myoblast differentiation. Also, our dataset includes the transcriptional profile of the epithelial cells localized in the presumptive hinge and notum of third instar larval wing discs. In addition we studied the functional relevance of Amalgam in flight muscle development by depleting Ama expression specifically in the adult muscle precursors. We determined the transcriptional changes and perturbations in AMP cell identity upon Ama knockdown.
Project description:Honey bees move through a series of in-hive tasks (“nursing”) to outside tasks (“foraging”) that coincident with an intense increase in metabolic activity. Social context can cause worker bees to speed up, or slow down this process and foragers may revert back to their earlier in hive tasks accompanied by reversion to earlier physiological states. To determine if the transcriptional profile of forager bees can revert, or if the effects of flight on gene expression are irreversible, we used whole-genome microarrays. Brain tissue and flight muscle exhibited independent patterns of expression during behavioral transitions, with patterns of expression in the brain reflecting both age and behavior, while flight muscle exhibited primarily age-related patterns of expression. Our data suggest that the transition from little to no flight (nurse) to intense flight (forager), rather than the amount of flight has a major effect on gene expression. Following behavioral reversion there was a partial reversion in gene expression but some aspects of forager expression patterns, such as those for genes involved in immune function, remained. These data suggest an epigenetic control and energy balance role in honey bee functional senescence. Brains and thoraces from the same individuals of all behavioral groups were compared on a total of 132 arrays. The samples were hybridized against each other using a loop design. The groups tested are outlined as follows: Typical aged nurse 'YN' (8-10 days old; <1 day flight experience), Precocious forager 'PF' (8 to 10 days old; 2 to 3 days flight experience), Overaged nurse 'ON' (19 to 22 days old; < 1 day flight experience), Forager - low flight 'TFL' (19 to 22 days old; 2 to 3 days flight experience), Forager - high flight 'TFH' ( 19 to 22 days old; 7 to 9 days flight experience), Forager - old 'OF' (25 to 26 days old; 10 to 12 days flight experience), Reverted nurse 'RN' (25 to 26 days old; 7 to 9 days flight experience). The comparisons are outlined as follows: YN:ON (6 arrays), ON:RN (6 arrays), RN:TFH (6 arrays), TFH:TFL (6 arrays), TFL:PF (6 arrays), PF:YN (6 arrays), ON:TFL (12 arrays), YN:OF (6 arrays), OF:RN (6 arrays), RN:YN (6 arrays). Each comparison was done for individual brains and thoraces. Total: 132 arrays
Project description:Muscles organise a pseudo-crystalline array of actin, myosin and titin filaments to build force-producing sarcomeres. To study how sarcomeres are built, we performed mRNA-sequencing of developing Drosophila flight muscles and identified 40 distinct expression profile clusters. Strikingly, two clusters are strongly enriched for sarcomeric components. Temporal gene expression together with detailed morphological analysis enabled us to define two distinct phases of sarcomere development, both of which require the transcriptional regulator Spalt major. During the first sarcomere formation phase, 2.0 µm long immature sarcomeres assemble myofibrils that spontaneously contract. In the second sarcomere maturation phase, sarcomeres grow to their final 3.2 µm length and 1.5 µm diameter and acquire stretch-sensitivity. Interestingly, the final number of myofibrils per flight muscle fiber is determined at the onset of the first phase and remains constant. Together, this defines a biphasic mode of sarcomere and myofibril morphogenesis – a new concept which may also apply to vertebrate muscle or heart development. Overall design: Part I: An 8-point timecourse of wild-type flight muscle development in Drosophila melanogaster was analyzed with duplicates/triplicates for each timepoint Part II: A Mef2-Gal4 x salmIR timecourse in duplicate at 4 timepoints was compared to wild-type flight muscle
Project description:Microgravity exposure as well as chronic muscle disuse are two of the main causes of physiological adaptive skeletal muscle atrophy in humans and murine animals in physiological condition. The aim of this study was to investigate, at both morphological and global gene expression level, skeletal muscle adaptation to microgravity in mouse soleus and extensor digitorum longus (EDL). Adult male mice C57BL/N6 were flown aboard the BION-M1 biosatellite for 30 days on orbit (BF) or housed in a replicate flight habitat on Earth (BG) as reference flight control. In this study, we investigated for the first time gene expression adaptation to 30 days of microgravity exposure in mouse soleus and EDL, highlighting potential new targets for improvement of countermeasures able to ameliorate or even prevent microgravity-induced atrophy in future spaceflights. Overall design: C57BL/N6 mice were randomly divided in 3 groups: Bion Flown (BF), mice flown aboard the Bion M1 biosatellite in microgravity environment for 30 days; Bion Ground (BG), mice housed in the same habitat of flown animals but exposed to earth gravity; and Flight Control (FC), mice housed in a standard animal facility.
Project description:Microgravity as well as chronic muscle disuse are two causes of low back pain originated at least in part from paraspinal muscle deconditioning. At present no study investigated the complexity of the molecular changes in human or mouse paraspinal muscles exposed to microgravity. The aim of this study was to evaluate longissimus dorsi and tongue (as a new potential in-flight negative control) adaptation to microgravity at global gene expression level. C57BL/N6 male mice were flown aboard the BION-M1 biosatellite for 30 days (BF) or housed in a replicate flight habitat on ground (BG). . Global gene expression analysis identified 89 transcripts differentially regulated in longissimus dorsi of BF vs. BG mice (False Discovery Rrate < 0,05 and fold change < -2 and > +2), while only a small number of genes were found differentially regulated in tongue muscle ( BF vs. BG = 27 genes). Overall design: C57BL/N6 mice were randomly divided in 3 groups: Bion Flown (BF), mice flown aboard the Bion M1 biosatellite in microgravity environment for 30 days; Bion Ground (BG), mice housed in the same habitat of flown animals but exposed to earth gravity; and Flight Control (FC), mice housed in a standard animal facility.
Project description:Transcriptional profiling comparing adult wild-type indirect flight muscle (IFM) with wild-type leg muscle and salm RNAi IFM (Mef2-GAL4, UASsalmIR). We used 2 different salm hairpin constructs for the experiments, TF3029 and TF101052, both available from the VDRC Drosophila stock centre. Experiments were done in biological duplicates + 1 technical replicate (1 labeled sample was hybridized on a different array)
Project description:Transcriptional profiling comparing adult wild-type indirect flight muscle (IFM) with wild-type leg muscle and salm RNAi IFM (Mef2-GAL4, UASsalmIR). We used 2 different salm hairpin constructs for the experiments, TF3029 and TF101052, both available from the VDRC Drosophila stock centre. Overall design: Experiments were done in biological duplicates + 1 technical replicate (1 labeled sample was hybridized on a different array)