Project description:Nucleus is a highly structured organelle and contains many functional compartments. While the structural basis for this complex spatial organization of compartments is unknown, a major component of this organization is likely to be the non-chromatin scaffolding called nuclear matrix (NuMat). Experimental evidence over the past decades indicates that most of the nuclear functions are at least transiently associated with the NuMat although the components of NuMat itself are poorly known. Here, we report NuMat proteome analysis from Drosophila melanogaster embryos and discuss its links with nuclear architecture and functions. In the NuMat proteome, we find structural proteins, chaperones related, DNA/RNA binding, chromatin remodeling and transcription factors. This complexity of NuMat proteome is an indicator of its structural and functional significance. Comparison of the 2D profile of NuMat proteome from different developmental stages of Drosophila embryos shows that less than half of the NuMat proteome is constant and rest of the proteins are stage specific dynamic components. This NuMat dynamics suggests a possible functional link between NuMat and the embryonic development. Finally, we also show that a subset of NuMat proteins remain associated with the mitotic chromosomes implicating their role in mitosis and possibly the epigenetic cellular memory. NuMat proteome analysis provides tools and opens up ways to understand nuclear organization and function.
Project description:As we age, structural changes contribute to progressive decline in organ function, which in the heart acts through poorly characterized mechanisms. Utilizing the rapidly aging fruit fly model with its significant homology to the human cardiac proteome, we found that cardiomyocytes exhibit progressive loss of Lamin C (mammalian Lamin A/C homologue) with age. Unlike other tissues and laminopathies, we observe decreasing nuclear size, while nuclear stiffness increases. Premature genetic reduction of Lamin C phenocopies aging’s effects on the nucleus, and subsequently decreases heart contractility and sarcomere organization. Surprisingly, Lamin C reduction downregulates myogenic transcription factors and cytoskeletal regulators, possibly via reduced chromatin accessibility. Subsequently, we find an adult-specific role for cardiac transcription factors and show that maintenance of Lamin C sustains their expression and prevents age-dependent cardiac decline. Our findings are conserved in aged non-human primates and mice, demonstrating age-dependent nuclear remodeling is a major mechanism contributing to cardiac dysfunction.
Project description:As we age, structural changes contribute to progressive decline in organ function, which in the heart acts through poorly characterized mechanisms. Utilizing the rapidly aging fruit fly model with its significant homology to the human cardiac proteome, we found that cardiomyocytes exhibit progressive loss of Lamin C (mammalian Lamin A/C homologue) with age. Unlike other tissues and laminopathies, we observe decreasing nuclear size, while nuclear stiffness increases. Premature genetic reduction of Lamin C phenocopies aging’s effects on the nucleus, and subsequently decreases heart contractility and sarcomere organization. Surprisingly, Lamin C reduction downregulates myogenic transcription factors and cytoskeletal regulators, possibly via reduced chromatin accessibility. Subsequently, we find an adult-specific role for cardiac transcription factors and show that maintenance of Lamin C sustains their expression and prevents age-dependent cardiac decline. Our findings are conserved in aged non-human primates and mice, demonstrating age-dependent nuclear remodeling is a major mechanism contributing to cardiac dysfunction.
Project description:We investigated the differential phosphoproteome of the mouse heart after isoproterenol stimulus of the AC3-I and AC3-C mice. The former is a model of specific in vivo CaMKII inhibition by a transgenically expressed peptide, whereas the latter is a transgenic mouse expressing a control peptide. Data processing: all raw data files of the individual SCX fractions of each of the 2 mouse experiments were imported into Proteome Discoverer v1.3.0.339 and the combined peak list was split into CID and HCD data (where applicable) before database searching. Subsequently, CID and HCD peak lists were searched individually against an International Protein Index (IPI; http://www.ebi.ac.uk/ipi) database containing mouse sequences and common contaminants such as bovine serum albumin and human keratins (IPI-Mouse v3.84; 60 248 sequences) through a direct connection to our in-house Mascot server (Mascot v2.3.2, Matrix Science, London, UK). The following settings were used: carbamidomethylation on cysteines as static modification; light, intermediate, and heavy dimethylation of peptide N-termini and lysine side chains, as well as oxidation on methionine and phosphorylation on serine, threonine, or tyrosine as variable modifications; and precursor mass tolerance of 20 ppm and 0.8 Da on the fragment masses (for CID) but 20 ppm and 0.02 Da for HCD searching. The enzyme was specified as trypsin, and 2 missed cleavages were allowed.
Project description:Nowadays, although single-cell multi-omics technologies are undergoing rapid development, simultaneous transcriptome and proteome analysis of a single-cell individual still faces great challenges. Here, we developed a single-cell simultaneous transcriptome and proteome (scSTAP) analysis platform based on microfluidics, high-throughput sequencing and mass spectrometry technology, to achieve deep and joint quantitative analysis of transcriptome and proteome at the single-cell level, providing an important resource for understanding the relationship between transcription and translation in cells. This platform was applied to analyze single mouse oocytes at different meiotic maturation stages, reaching an average quantification depth of 19948 genes and 2663 protein groups in single mouse oocytes.