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Transcription factors play key roles in cell-fate decisions by regulating 3D genome conformation and gene expression. The traditional view is that methylation of DNA hinders transcription factors binding to them, but recent research has shown that many transcription factors prefer to bind to methylated DNA. Therefore, identifying such transcription factors and understanding their functions is a stepping-stone for studying methylation-mediated biological processes. In this paper, a two-step discriminated method was proposed to recognize transcription factors and their preference for methylated DNA based only on sequences information. In the first step, the proposed model was used to discriminate transcription factors from non-transcription factors. The areas under the curve (AUCs) are 0.9183 and 0.9116, respectively, for the 5-fold cross-validation test and independent dataset test. Subsequently, for the classification of transcription factors that prefer methylated DNA and transcription factors that prefer non-methylated DNA, our model could produce the AUCs of 0.7744 and 0.7356, respectively, for the 5-fold cross-validation test and independent dataset test. Based on the proposed model, a user-friendly web server called TFPred was built, which can be freely accessed at http://lin-group.cn/server/TFPred/., Graphical Abstract, Transcription factors binding to methylated DNA perform special and unclear functions. Lin and colleagues developed a machine-learning-based method to predict transcription factors and their preference for methylated DNA, which will help the discovery of methylated DNA-bound transcription factors and the study of their functions.

The way in which living organisms mobilize a combination of long-term adaptive mechanisms and short-term phenotypic plasticity to face environmental variations is still largely unknown. In the context of climate change, understanding the genetic and epigenetic bases for adaptation and plasticity is a major stake for preserving genomic resources and the resilience capacity of livestock populations. We characterized both epigenetic and genetic variations by contrasting 22 sheep and 21 goats from both sides of a climate gradient, focusing on free-ranging populations from Morocco. We produced for each individual Whole-Genome Sequence at 12X coverage and MeDIP-Seq data, to identify regions under selection and those differentially methylated. For both species, the analysis of genetic differences (FST) along the genome between animals from localities with high vs. low temperature annual variations detected candidate genes under selection in relation to environmental perception (5 genes), immunity (4 genes), reproduction (8 genes) and production (11 genes). Moreover, we found for each species one differentially methylated gene, namely AGPTA4 in goat and SLIT3 in sheep, which were both related, among other functions, to milk production and muscle development. In both sheep and goats, the comparison between genomic regions impacted by genetic and epigenetic variations suggests that climatic variations impacted similar biological pathways but different genes.

// Mario Menschikowski 1 , Carsten Jandeck 1 , Markus Friedemann 1 , Brit Nacke 1 , Saskia Hantsche 1 , Oliver Tiebel 1 , Olga Sukocheva 2 and Albert Hagelgans 1 1 Institute of Clinical Chemistry and Laboratory Medicine, Carl Gustav Carus University Hospital, Technical University of Dresden, Dresden, Germany 2 School of Health Sciences, Flinders University of South Australia, Adelaide, Australia Correspondence to: Mario Menschikowski, email: Mario.Menschikowski@uniklinikum-dresden.de Keywords: liquid biopsy; free circulating DNA (fc-DNA); methylated DNA; tumor DNA; digital PCR Received: June 30, 2018 Accepted: October 24, 2018 Published: November 16, 2018 ABSTRACT Background: The analysis of aberrant DNA methylations is used for the diagnosis of cancer as significant changes in the gene methylation pattern are often detected during early carcinogenesis. In this study, we evaluated the performance of a two-step method that combines pre-amplification with ddPCR technique. Results: By using ddPCR, the dependence of amplification efficiency for methylated and unmethylated DNA fragments on the relevant MgCl 2 concentration and the annealing temperature was established in addition to the primer design. We found that the efficiency can be adjusted toward methylated sequences by using primers covering one to four CpG sites under appropriately selected MgCl 2 concentration and annealing temperature. Applying a PCR bias between 85% and 95%, five copies of methylated tumor DNA fragments were detected against a background of 700,000 copies of unmethylated DNA fragments with a high signal-to-noise ratio. The analysis of serum samples from patients with prostate cancer showed a significantly improved performance of the new method in comparison with the MS-HRM technique, ddPCR alone, or ddPCR in combination with an unbiased pre-amplification using methylation-independent primers. Conclusions: We define this method as an optimized bias-based pre-amplification-digital droplet PCR (OBBPA-ddPCR) technique. This novel method is recommended for the early detection of cancer-specific DNA methylation biomarkers in the form of a liquid biopsy.

Aberrantly methylated genes are increasingly being established as biomarkers for the detection of colorectal cancer (CRC). In the present study, the methylation levels of the secreted frizzled-related protein gene 2 (SFRP2), GATA binding protein 4/5 (GATA4/5), N-Myc downstream-regulated gene 4 (NDRG4) and vimentin (VIM) promoters were evaluated for their use as markers in the noninvasive detection of CRC. Methylation-specific polymerase chain reaction was performed to analyze promoter CpG methylation of SFRP2, GATA4/5, NDRG4 and VIM in the fecal DNA of 56 patients with CRC and 40 individuals exhibiting normal colonoscopy results. Promoter methylation levels of SFRP2, GATA4/5, NDRG4 and VIM in CRC patients were 57.1% (32/56), 42.9% (24/56), 83.9% (47/56), 28.6% (16/56) and 41.1% (23/56), respectively. Furthermore, the specificity of the genes were 90.0% (4/40), 95.0% (2/40), 82.5% (7/40), 97.5% (4/40) and 85.0% (6/40), respectively. The overall sensitivity of detection for fecal DNA with at least one methylated gene was 96.4% (54/56) in CRC patients. By contrast, only 14 of the 40 normal individuals exhibited methylated DNA in the aforementioned promoter regions. Methylation of the SFRP2, GATA4/5, NDRG4 and VIM promoters in fecal DNA is associated with the presence of colorectal tumors. Therefore, the detection of aberrantly methylated DNA in fecal samples may present a promising, noninvasive screening method for CRC.

Molecular biology has evolved far beyond that which could have been predicted at the time DNA identity testing was established. Indeed we should now perhaps be referring to "forensic molecular biology." Aside from DNA's established role in identifying the "who" in crime investigations, other developments in medical and developmental molecular biology are now ripe for application to forensic challenges. The impact of DNA methylation and other post-fertilization DNA modifications, plus the emerging role of small RNAs in the control of gene expression, is re-writing our understanding of human biology. It is apparent that these emerging technologies will expand forensic molecular biology to allow for inferences about "when" a crime took place and "what" took place. However, just as the introduction of DNA identity testing engendered many challenges, so the expansion of molecular biology into these domains will raise again the issues of scientific validity, interpretation, probative value, and infringement of personal liberties. This Commentary ponders some of these emerging issues, and presents some ideas on how they will affect the conduct of forensic molecular biology in the foreseeable future. © 2014 Gunn, Walsh and Roux.

Methyl-CpG-binding protein 2 (MeCP2) is generally considered to act as a transcriptional repressor, whereas recent studies suggest that MeCP2 is also involved in transcription activation. To gain insight into this dual function of MeCP2, we assessed the impact of MeCP2 on higher-order chromatin structure in living cells using mammalian cell systems harbouring a lactose operator and reporter gene-containing chromosomal domain to assess the effect of lactose repressor-tagged MeCP2 (and separate MeCP2 domains) binding in living cells. Our data reveal that targeted binding of MeCP2 elicits extensive chromatin unfolding. MeCP2-induced chromatin unfolding is triggered independently of the methyl-cytosine-binding domain. Interestingly, MeCP2 binding triggers the loss of HP1 gamma at the chromosomal domain and an increased HP1 gamma mobility, which is not observed for HP1 alpha and HP1 beta. Surprisingly, MeCP2-induced chromatin unfolding is not associated with transcriptional activation. Our study suggests a novel role for MeCP2 in reorganizing chromatin to facilitate a switch in gene activity.

It is now widely accepted that there is a need for the development of molecular markers of cancer that can be used for clinical prognostication and monitoring. Approximately a decade ago tumor-derived circulating nucleic acids in the plasma or serum (CNAPS) of cancer patients were introduced as a noninvasive tool for cancer detection. This review focuses on the various types of CNAPS of patients with solid neoplasias (genetic alterations in circulating DNA, microsatellites, methylated DNA, viral DNA, nucleosomes, mitochondrial DNA and cell-free mRNA) and their putative potential as prognostic or predictive parameter or even as a tool for therapy monitoring during follow-up. Additionally, this review aims to point out the difference between a prognostic and a predictive factor in patient bloodstream. However, with rapid technical improvement and well-designed studies we conclude that the next years will see CNAPS analysis integrated in the prognostication and monitoring of cancer patients, thus producing more specific treatment regimens for patients with various stages of neoplastic disease and ultimately longer survival and better quality of life.

Kaiso is a Cys2His2 zinc finger (ZF) protein that mediates methyl-CpG-dependent and sequence-specific transcriptional repression. As a first step towards elucidating the structural and molecular basis for recognition of these disparate DNA sequences, the minimal binding region of Kaiso was identified and optimal DNA sequences for high-affinity interactions were characterized. Contrary to previous findings, Kaiso requires all three zinc fingers plus adjacent protein regions for DNA recognition. An N-terminal extension contributes to structural stability, while an extended C-terminal region augments DNA binding. Complexes formed between the optimized Kaiso construct and both DNA sequences are suitable for future structural evaluation.