Project description:Shells of pearl oyster are natural biominerals with remarkable properties and can be repaired after damage, which are regulated by biomacromolcules especially shell matrix proteins (SMPs). Identifying SMPs is critical for further understanding the process. Although proteomic methods have been used to reveal the complex protein mixture in mature shells, the proteomics of repaired shells after shell damage have not been reported before. Here, we studied the SMPs of the repaired shells (prismatic layers) 5-10 days after shell damage in Pinctada fucata by integrating transcriptomics and proteomics and compared the microstructure difference between repaired and mature shells. Although the repaired shells are calcite, similar to mature shells, the microstructure of repaired shells has holes in the center of prisms with irregular and curved edges. In total, we found 49 SMPs from the repaired shells including some proteins only existing in mature nacreous layers. Peroxidase-like protein and beta-N-acetylhexosaminidase may be important players in repaired shells. In addition, they have the capability to affect CaCO3 crystallization process in vitro, altering the packing and reducing the crystallinity of crystals. This study could improve our understanding of shell repair process and lay the foundation for studying SMPs-controlled biomineralization.
Project description:ChIP-seq analysis of SNAIL binding sites in RH30 cells was performed to discover novel SNAIL binding sites in rhabdmyosarcoma cells.
Project description:Pathways underlying miRNA biogenesis, degradation, and activity were established early in land plant evolution, but the 24-nt siRNA pathway that guides DNA methylation was incomplete in early land plants, especially lycophytes. We show that the functional diversification of key gene families such as DICER-LIKE and ARGONAUTE (AGO) as observed in angiosperms occurred early in land plants followed by parallel expansion of the AGO family in ferns and angiosperms. We uncovered an unexpected AGO family specific to lycophytes and ferns. Our phylogenetic analyses of miRNAs in lycophytes, bryophytes, ferns, and angiosperms refined the temporal origination of conserved miRNA families in land plants.
Project description:In skeletal myogenesis, the transcription factor MyoD activates distinct transcriptional programs in progenitors compared to terminally differentiated cells. Using ChIP-seq and gene expression analyses, we show that in primary myoblasts, Snail-HDAC1/2 repressive complex bind and exclude MyoD from its targets. Notably, Snail binds E-box motifs that are G/C-rich in their central dinucleotides, and such sites are almost exclusively associated with genes expressed during differentiation. By contrast, Snail does not bind the A/T-rich E-boxes associated with MyoD targets in myoblasts. Thus, Snai1-HDAC1/2 prevents MyoD occupancy on differentiation-specific regulatory elements and the change from Snail- to MyoD-binding often results in enhancer switching during differentiation. Furthermore, we show that a regulatory network involving Myogenic Regulatory Factors (MRFs), Snail/2, miR-30a and miR-206 acts as a molecular switch that controls entry into myogenic differentiation. Together, these results reveal a regulatory paradigm that directs distinct gene expression programs in progenitors versus terminally differentiated cells. Genome wide binding sites of various transcription factors and chromatin modifiers in muscle cells
Project description:The transcription factor Snail is known as an EMT regulator to promote cancer metastasis. Identification Snail-regulated miRNAs helps to uncover mechanisms governing CRC metastasis