Background CGGBP1 is a repeat-binding protein with diverse functions in the regulation of gene expression, cytosine methylation, repeat silencing and genomic integrity. CGGBP1 has also been identified as a cooperator of histone-modifying enzymes and as a component of CTCF-containing complexes that regulate the enhancer–promoter looping. CGGBP1–CTCF cross talk in chromatin regulation has been hitherto unknown. Results Here, we report that the occupancy of CTCF at repeats depends on CGGBP1. Using ChIP-sequencing for CTCF, we describe its occupancy at repetitive DNA. Our results show that endogenous level of CGGBP1 ensures CTCF occupancy preferentially on repeats over canonical CTCF motifs. By combining CTCF ChIP-sequencing results with ChIP sequencing for three different kinds of histone modifications (H3K4me3, H3K9me3 and H3K27me3), we show that the CGGBP1-dependent repeat-rich CTCF-binding sites regulate histone marks in flanking regions. Conclusion CGGBP1 affects the pattern of CTCF occupancy. Our results posit CGGBP1 as a regulator of CTCF and its binding sites in interspersed repeats.

ObjectivesAlthough CpG methylation is well studied, mechanisms of non-CpG methylation in mammals remains elusive. Studying proteins with non-CpG cytosine methylation-sensitive DNA-binding, such as human CGGBP1, can unveil cytosine methylation regulatory mechanisms. Here we have resequenced a published genome-wide bisulfite sequencing library and analyzed it at base level resolution. CpG, CHG and CHH (where H is any nucleotide other than G) methylation states in non-targeting or CGGBP1-targeting shmiR lentivirus-transduced cells have been analyzed to identify how CGGBP1 regulates CpG and non-CpG methylation.ResultsWe report that CGGBP1 acts as a dynamic bimodal balancer of methylation. Both gain and loss of methylation observed upon CGGBP1 depletion were spatially overlapping at annotated functional regions and not identifiable with any sequence motifs but clearly associated with GC-skew. CGGBP1 depletion caused clustered methylation changes in cis, upstream of R-loop forming promoters. This was complemented by clustered occurrences of methylation changes in proximity of transcription start sites of known cytosine methylation regulatory genes, altered expression of which can regulate cytosine methylation in trans. Despite low coverage, our data provide reliable estimates of the spectrum of methylation changes regulated by CGGBP1 in all cytosine contexts genome-wide through a combination of cis and trans-acting mechanisms.Electronic supplementary materialThe online version of this article (10.1186/s13104-018-3516-1) contains supplementary material, which is available to authorized users.

Background: Online cardiovascular health materials are easily accessible with an Internet connection, but the readability of its content may limit practical use by patients. Objective: The goal of our study was to assess the readability of the most commonly searched Internet health education materials for cardiovascular diseases accessed via Google. Methods: We selected 20 commonly searched cardiovascular disease terms: aneurysm, angina, atherosclerosis, cardiomyopathy, congenital heart disease, coronary artery disease, deep vein thrombosis, heart attack, heart failure, high blood pressure, pericardial disease, peripheral arterial disease, rheumatic heart disease, stroke, sudden death, valvular heart disease, mini-stroke, lower extremity edema, pulmonary embolism, and exertional dyspnea. Terms were selected on Google and selected up to 10 results in order of presentation in the search results by reviewing a maximum of 15 pages of Google search results specifically providing education toward patients to yield 196 total patient education articles. Key Results: All readability measures assessing grade level measures found the 196 articles were written at a mean 10.9 ( SD = 1.8) grade reading level. Moreover, 99.5% of the articles were written beyond the 5th- to 6th-grade level recommended by the American Medical Association. Conclusions: Given the prominent use of online patient education material, we consider readability as a quality metric that should be evaluated prior to online publication of any health education materials. Further study of how to improve the readability of online materials may enhance patient education, engagement, and health outcomes. [ HLRP: Health Literacy Research and Practice . 2019;3(2):e74–e80.] Plain Language Summary: Patients often use Google as a tool for understanding their medical conditions. This study examined the readability of articles accessed via Google for commonly searched cardiovascular diseases and found all articles were written above reading grade levels appropriate for patients. We hope this study will promote the importance of ensuring that online patient education articles are written at appropriate reading levels.

Background The human CGGBP1 binds to GC-rich regions and interspersed repeats, maintains homeostasis of stochastic cytosine methylation and determines DNA-binding of CTCF. Interdependence between regulation of cytosine methylation and CTCF occupancy by CGGBP1 remains unknown. Results By analyzing methylated DNA-sequencing data obtained from CGGBP1-depleted cells, we report that some transcription factor-binding sites, including CTCF, resist stochastic changes in cytosine methylation. By analysing CTCF-binding sites we show that cytosine methylation changes at CTCF motifs caused by CGGBP1 depletion resist stochastic changes. These CTCF-binding sites are positioned at locations where the spread of cytosine methylation in cis depends on the levels of CGGBP1. Conclusion Our findings suggest that CTCF occupancy and functions are determined by CGGBP1-regulated cytosine methylation patterns.

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