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Purification of proteins associated with specific genomic Loci.

ABSTRACT: Eukaryotic DNA is bound and interpreted by numerous protein complexes in the context of chromatin. A description of the full set of proteins that regulate specific loci is critical to understanding regulation. Here, we describe a protocol called proteomics of isolated chromatin segments (PICh) that addresses this issue. PICh uses a specific nucleic acid probe to isolate genomic DNA with its associated proteins in sufficient quantity and purity to allow identification of the bound proteins. Purification of human telomeric chromatin using PICh identified the majority of known telomeric factors and uncovered a large number of novel associations. We compared proteins found at telomeres maintained by the alternative lengthening of telomeres (ALT) pathway to proteins bound at telomeres maintained by telomerase. We identified and validated several proteins, including orphan nuclear receptors, that specifically bind to ALT telomeres, establishing PICh as a useful tool for characterizing chromatin composition.

SUBMITTER: Dejardin J

PROVIDER: S-EPMC3395431 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature

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Purification of proteins associated with specific genomic Loci.

Déjardin Jérôme J Kingston Robert E RE

Cell 20090101 1

Eukaryotic DNA is bound and interpreted by numerous protein complexes in the context of chromatin. A description of the full set of proteins that regulate specific loci is critical to understanding regulation. Here, we describe a protocol called proteomics of isolated chromatin segments (PICh) that addresses this issue. PICh uses a specific nucleic acid probe to isolate genomic DNA with its associated proteins in sufficient quantity and purity to allow identification of the bound proteins. Purif ...[more]

PMID: 19135898

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Project description:Aiming to identify more genomic loci associated with bone mineral density (BMD), we conducted a joint association analysis of 2 genome-wide association study (GWAS) by the integrative association method multi-trait analysis of GWAS (MTAG). The first one is the single GWAS of estimated heel BMD (eBMD) in the UK biobank (UKB) cohort (N = 426,824), and the second one is the GWAS meta-analysis of total body BMD (TB-BMD) in 66,628 participants from 30 studies. Approximate conditional association analysis was performed in the identified novel loci to identify secondary association signal. Statistical fine-mapping was conducted to prioritize plausible credible risk variants (CRVs). Candidate genes were prioritized based on the analyses of cis- expression quantitative trait locus (cis-eQTL) and cis-protein QTL (cis-pQTL) information as well as the functional category of the SNP. By integrating the information carried in over 490,000 participants, this largest joint analysis of BMD GWAS identified 12 novel genomic loci at the genome-wide significance level (GWS, p = 5.0 × 10-8), nine of which were for eBMD and four were for TB-BMD, explaining an additional 0.11 and 0.23% heritability for the two traits, respectively. These loci include 1p33 (lead SNP rs10493130, peBMD = 3.19 × 10-8), 5q13.2 (rs4703589, peBMD = 4.78 × 10-8), 5q31.3 (rs9324887, pTB-BMD = 1.36 × 10-9), 6p21.32 (rs6905837, peBMD = 3.32 × 10-8), 6q14.1 (rs10806234, peBMD = 2.63 × 10-8), 7q21.11 (rs10806234, pTB-BMD = 3.37 × 10-8), 8q24.12 (rs11995866, peBMD = 6.72 × 10-9), 12p13.31 (rs1639122, peBMD = 4.43 × 10-8), 12p12.1 (rs58489179, peBMD = 4.74 × 10-8), 12q24.23 (rs75499226, peBMD = 1.44 × 10-8), 19q13.31 (rs7255083, pTB-BMD = 2.18 × 10-8) and 22q11.23 (rs13056137, pTB-BMD = 2.54 × 10-8). All lead SNPs in these 12 loci are nominally significant in both original studies as well as consistent in effect direction between them, providing solid evidence of replication. Approximate conditional analysis identified one secondary signal in 5q13.2 (rs11738874, pconditional = 5.06 × 10-9). Statistical fine-mapping analysis prioritized 269 CRVs. A total of 65 candidate genes were prioritized, including those with known biological function to bone development (such as FGF1, COL11A2 and DEPTOR). Our findings provide novel insights into a better understanding of the genetic mechanism underlying bone development as well as candidate genes for future functional investigation.

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Purification of proteins associated with specific genomic Loci.

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Purification of proteins associated with specific genomic Loci.

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