Project description:Clarification of the mechanisms underlying osteoclast differentiation enable us to understand the physiology of bone metabolism as well as the pathophysiology of bone diseases, such as osteoporosis. Recently, it has been reported that epigenetics can determine the cell fate and regulate cell type specific gene expression. However, little is known about epigenetics during osteoclastogenesis. To reveal a part of epigenetics, especially focused on chromatin dynamics, during early osteoclastogenesis and identify novel transcription factors involved in osteoclastogenesis, we investigated genome-wide analysis of open chromatin during receptor activator of nuclear factor-M-NM-:B ligand (RANKL)-induced osteoclastogenesis using DNase I hypersensitive sites sequencing (DNase-seq). DNase-seq was performed using the extracted nuclei obtained from RAW264 cells treated with or without RANKL for 24 hours, followed by several bioinformatic analyses. DNase I hypersensitive sites (DHSs) during RANKL-induced osteoclastogenesis were dynamically changed and accumulated in promoter regions, although the distributions of DHSs among cis-regulatory DNA regions were identical regardless of RANKL stimulation. Motif discoveries from DHSs successfully identified well-known osteoclastogenic transcription factors such as Jun, CREB1, FOS, ATF2 and ATF4, but also novel transcription factors for osteoclastogenesis such as Zscan10, Atf1 Nrf1 and Srebf2. siRNA knockdown of these identified novel transcription factors impaired osteoclastogenesis. Taken together, DNase-seq can be a useful tool for comprehension of epigenetics, especially chromatin dynamics during osteoclastogenesis and for identification of novel transcription factors involved in osteoclastogenesis. This study may reveal underlying mechanisms that determine cell-type specific differentiation of bone cells and may lead to investigate novel therapeutic targets for osteoporosis. Examination of genome-wide DNase Hypersensitive Sites in differentiated and undifferentiated RAW264 cells.
Project description:Clarification of the mechanisms underlying osteoclast differentiation enable us to understand the physiology of bone metabolism as well as the pathophysiology of bone diseases, such as osteoporosis. Recently, it has been reported that epigenetics can determine the cell fate and regulate cell type specific gene expression. However, little is known about epigenetics during osteoclastogenesis. To reveal a part of epigenetics, especially focused on chromatin dynamics, during early osteoclastogenesis and identify novel transcription factors involved in osteoclastogenesis, we investigated genome-wide analysis of open chromatin during receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis using DNase I hypersensitive sites sequencing (DNase-seq). DNase-seq was performed using the extracted nuclei obtained from RAW264 cells treated with or without RANKL for 24 hours, followed by several bioinformatic analyses. DNase I hypersensitive sites (DHSs) during RANKL-induced osteoclastogenesis were dynamically changed and accumulated in promoter regions, although the distributions of DHSs among cis-regulatory DNA regions were identical regardless of RANKL stimulation. Motif discoveries from DHSs successfully identified well-known osteoclastogenic transcription factors such as Jun, CREB1, FOS, ATF2 and ATF4, but also novel transcription factors for osteoclastogenesis such as Zscan10, Atf1 Nrf1 and Srebf2. siRNA knockdown of these identified novel transcription factors impaired osteoclastogenesis. Taken together, DNase-seq can be a useful tool for comprehension of epigenetics, especially chromatin dynamics during osteoclastogenesis and for identification of novel transcription factors involved in osteoclastogenesis. This study may reveal underlying mechanisms that determine cell-type specific differentiation of bone cells and may lead to investigate novel therapeutic targets for osteoporosis.
Project description:Gene expression is controlled by the complex interaction of transcription factors binding to promoters and other regulatory DNA elements. One common characteristic of the genomic regions associated with regulatory proteins is a pronounced sensitivity to DNase I digestion. We generated genome-wide high resolution maps of DNase I hypersensitive (DH) sites from both seedling and callus tissues of rice. Approximately 25% of the DH sites from both tissues were found in the putative promoters, indicating that the vast majority of gene regulatory elements in rice are not located at promoter regions. We found 58% more DH sites in callus than in seedling. For DH sites detected in both seedling and callus, 31% displayed significantly different levels of DNase I sensitivity within the two tissues. Genes that were differentially expressed in seedling and callus were frequently associated with DH sites in both tissues. The DNA sequences contained within the DH sites were hypomethylated, consistent with what is known about active gene regulatory elements. Interestingly, tissue-specific DH sites located in the promoters showed an elevated level of DNA methylation. A distinct elevation of H3K27me3 was associated with intergenic DH sites. These results suggest that epigenetic modifications play a role in the dynamic changes of the numbers and DNase I sensitivity of DH sites during development. Generation of genome-wide high resolution maps of DNase I hypersensitive sites in two tissues of rice. For seedling, we constructed 3 libraries (biological replicates) and sequenced a lane of Illumina Genome Analyzer for each library. For callus, we constructed 2 libraries (biological replicates). We sequenced two lanes for one library and one lane for another library.
Project description:Gene expression is controlled by the complex interaction of transcription factors binding to promoters and other regulatory DNA elements. One common characteristic of the genomic regions associated with regulatory proteins is a pronounced sensitivity to DNase I digestion. We generated genome-wide high resolution maps of DNase I hypersensitive (DH) sites from both seedling and callus tissues of rice. Approximately 25% of the DH sites from both tissues were found in the putative promoters, indicating that the vast majority of gene regulatory elements in rice are not located at promoter regions. We found 58% more DH sites in callus than in seedling. For DH sites detected in both seedling and callus, 31% displayed significantly different levels of DNase I sensitivity within the two tissues. Genes that were differentially expressed in seedling and callus were frequently associated with DH sites in both tissues. The DNA sequences contained within the DH sites were hypomethylated, consistent with what is known about active gene regulatory elements. Interestingly, tissue-specific DH sites located in the promoters showed an elevated level of DNA methylation. A distinct elevation of H3K27me3 was associated with intergenic DH sites. These results suggest that epigenetic modifications play a role in the dynamic changes of the numbers and DNase I sensitivity of DH sites during development. To do associated analysis with DNase I hypersensitive sites in rice, we performed ChIP-seq to identify the positions of three histone modifications (H3K4me2, H3K36me3 and H4K12ac) in the rice genome (leaf tissue only - not callus). The ChIP DNA from seedling of each experiment was sequenced on one lane of Illumina Genome Analyzer.
Project description:Adipogenesis is tightly controlled by a complex network of transcription factors acting at different stages of differentiation. Peroxisome proliferator-activated receptor gamma (PPAR gamma) and CCAAT/enhancer binding protein (C/EBP) family members are key regulators of this process. We have employed DNase I hypersensitive site analysis to investigate the genome-wide changes in chromatin structure that accompany the binding of adipogenic transcription factors. These analyses revealed a dramatic and dynamic modulation of the chromatin landscape during the first hours of adipocyte differentiation that coincides with cooperative binding of multiple early transcription factors (including glucocorticoid receptor, retinoid X receptor, Stat5a, C/EBPbeta and -delta) to transcription factor 'hotspots'. Our results demonstrate that C/EBPbeta marks a large number of these transcription factor 'hotspots' prior to induction of differentiation and chromatin remodeling and is required for their establishment. Furthermore, a subset of early remodeled C/EBP binding sites persists throughout differentiation and is later occupied by PPAR gamma , indicating that early C/EBP family members, in addition to their well established role in activation of PPAR gamma transcription, may act as pioneering factors for PPAR gamma binding. DNase I hypersensitive chromatin regions and transcription factor binding sites were identified at various time points of 3T3-L1 differentiation using DHS-seq and ChIP-seq, respectively.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
Project description:This SuperSeries is composed of the following subset Series: GSE26610: DNase I hypersensitive sites in two tissues of rice GSE26733: ChIP-seq to identify the positions of three histone modifications in the rice genome Refer to individual Series