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: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.
Project description:To complement our existing data on developmental gene expression changes in flight muscle (IFM) development in Drosophila (GSE107247, GSE63707), we performed mRNA-Seq on dissected leg samples at three stages during pupal development (30, 50 and 72h APF). We further sequenced an additional timepoint at 24h APF for RNAi knockdown of aret (Bru1) in flight muscle. Comparison of splicing and expression profiles of sarcomeric genes allowed us to identify muscle-type specific differences in gene and isoform expression between fibrillar flight muscle and tubular leg muscle. We can further trace the dynamics of exon usage in sarcomere genes across the developmental timecourse, allowing us to identify events the switch during muscle differentiation and maturation.
Project description:Oxidative metabolism is the predominant energy source for muscle contraction. How this is transcriptionally regulated during muscle development to accommodate different metabolic requirements and muscle types is largely unknown. We show that the formation of mitochondria cristae harbouring the respiratory chain is concomitant with a large-scale transcriptional upregulation of genes linked with oxidative phosphorylation (OXPHOS) during the middle of Drosophila flight muscle development. We further demonstrate using high-resolution imaging, transcriptomic and biochemical analyses that Motif-1-binding protein (M1BP) transcriptionally regulates the expression of genes encoding critical components for OXPHOS complex assembly and integrity. In the absence of M1BP, mitochondrial respiratory complexes are improperly assembled and aggregate in the mitochondrial matrix, triggering a strong protein quality control response. Together, this study provides the first insight into the transcriptional regulation of oxidative metabolism during Drosophila myogenesis and identifies M1BP as a novel player in this process.
Project description:Oxidative metabolism is the predominant energy source for muscle contraction. How this is transcriptionally regulated during muscle development to accommodate different metabolic requirements and muscle types is largely unknown. We show that the formation of mitochondria cristae harbouring the respiratory chain is concomitant with a large-scale transcriptional upregulation of genes linked with oxidative phosphorylation (OXPHOS) during the middle of Drosophila flight muscle development. We further demonstrate using high-resolution imaging, transcriptomic and biochemical analyses that Motif-1-binding protein (M1BP) transcriptionally regulates the expression of genes encoding critical components for OXPHOS complex assembly and integrity. In the absence of M1BP, mitochondrial respiratory complexes are improperly assembled and aggregate in the mitochondrial matrix, triggering a strong protein quality control response. Together, this study provides the first insight into the transcriptional regulation of oxidative metabolism during Drosophila myogenesis and identifies M1BP as a novel player in this process.
Project description:Oxidative metabolism is the predominant energy source for muscle contraction. How this is transcriptionally regulated during muscle development to accommodate different metabolic requirements and muscle types is largely unknown. We show that the formation of mitochondria cristae harbouring the respiratory chain is concomitant with a large-scale transcriptional upregulation of genes linked with oxidative phosphorylation (OXPHOS) during the middle of Drosophila flight muscle development. We further demonstrate using high-resolution imaging, transcriptomic and biochemical analyses that Motif-1-binding protein (M1BP) transcriptionally regulates the expression of genes encoding critical components for OXPHOS complex assembly and integrity. In the absence of M1BP, mitochondrial respiratory complexes are improperly assembled and aggregate in the mitochondrial matrix, triggering a strong protein quality control response. Together, this study provides the first insight into the transcriptional regulation of oxidative metabolism during Drosophila myogenesis and identifies M1BP as a novel player in this process.
Project description:Oxidative metabolism is the predominant energy source for muscle contraction. How this is transcriptionally regulated during muscle development to accommodate different metabolic requirements and muscle types is largely unknown. We show that the formation of mitochondria cristae harbouring the respiratory chain is concomitant with a large-scale transcriptional upregulation of genes linked with oxidative phosphorylation (OXPHOS) during the middle of Drosophila flight muscle development. We further demonstrate using high-resolution imaging, transcriptomic and biochemical analyses that Motif-1-binding protein (M1BP) transcriptionally regulates the expression of genes encoding critical components for OXPHOS complex assembly and integrity. In the absence of M1BP, mitochondrial respiratory complexes are improperly assembled and aggregate in the mitochondrial matrix, triggering a strong protein quality control response. Together, this study provides the first insight into the transcriptional regulation of oxidative metabolism during Drosophila myogenesis and identifies M1BP as a novel player in this process.