The Experts below are selected from a list of 22629 Experts worldwide ranked by ideXlab platform

Hongjun Song - One of the best experts on this subject based on the ideXlab platform.

  • emerging roles of tet proteins and 5 hydroxymethylcytosines in active dna demethylation and beyond
    Cell Cycle, 2011
    Co-Authors: Yijing Su, Guo Li Ming, Chun Zhong, Hongjun Song
    Abstract:

    Cytosine methylation is the major Epigenetic Modification of metazoan DNA. Although there is strong evidence that active DNA demethylation occurs in animal cells, the molecular details of this process are unknown. The recent discovery of the TET protein family (TET1–3) 5-methylcytosine hydroxylases has provided a new entry point to reveal the identity of the long-sought DNA demethylase. Here, we review the recent progress in understanding the function of TET proteins and 5-hydroxymethylcytosine (5hmC) through various biochemical and genomic approaches, the current evidence for a role of 5hmC as an early intermediate in active DNA demethylation and the potential functions of TET proteins and 5hmC beyond active DNA demethylation. We also discuss how future studies can extend our knowledge of this novel Epigenetic Modification.

  • emerging roles of tet proteins and 5 hydroxymethylcytosines in active dna demethylation and beyond
    Cell Cycle, 2011
    Co-Authors: Yijing Su, Guo Li Ming, Chun Zhong, Hongjun Song
    Abstract:

    Cytosine methylation is the major Epigenetic Modification of metazoan DNA. Although there is strong evidence that active DNA demethylation occurs in animal cells, the molecular details of this process are unknown. The recent discovery of the TET protein family (TET1–3) 5-methylcytosine hydroxylases has provided a new entry point to reveal the identity of the long-sought DNA demethylase. Here, we review the recent progress in understanding the function of TET proteins and 5-hydroxymethylcytosine (5hmC) through various biochemical and genomic approaches, the current evidence for a role of 5hmC as an early intermediate in active DNA demethylation and the potential functions of TET proteins and 5hmC beyond active DNA demethylation. We also discuss how future studies can extend our knowledge of this novel Epigenetic Modification.

Young C Lin - One of the best experts on this subject based on the ideXlab platform.

  • zeranol down regulates p53 expression in primary cultured human breast cancer epithelial cells through Epigenetic Modification
    International Journal of Molecular Sciences, 2011
    Co-Authors: Robert Jen, Eric Feng, Saiyi Zhong, Shuhong Lin, Jieyu Liu, Young C Lin
    Abstract:

    Epidemiological studies have suggested that there are many risk factors associated with breast cancer. Silencing tumor suppressor genes through Epigenetic alterations play critical roles in breast cancer initiation, promotion and progression. As a growth promoter, Zeranol (Z) has been approved by the FDA and is widely used to enhance the growth of beef cattle in the United States. However, the safety of Z use as a growth promoter is still under debate. In order to provide more evidence to clarify this critical health issue, the current study investigated the effect of Z on the proliferation of primary cultured human normal and cancerous breast epithelial cells (PCHNBECs and PCHBCECs, respectively) isolated from the same patient using MTS assay, RT-PCR and Western blot analysis. We also conducted an investigation regarding the mechanisms that might be involved. Our results show that Z is more potent to stimulate PCHBCEC growth than PCHNBEC growth. The stimulatory effects of Z on PCHBCECs and PCHBCECs may be mediated by its down-regulating expression of the tumor suppressor gene p53 at the mRNA and protein levels. Further investigation showed that the expression of DNA methylatransferase 1 mRNA and protein levels is up-regulated by treatment with Z in PCHBCECs as compared to PCHNBECs, which suggests a role of Z in Epigenetic Modification involved in the regulation of p53 gene expression in PCHBCECs. Our experimental results imply the potentially adverse health effect of Z in breast cancer development. Further study is continuing in our laboratory.

  • abstract 5364 zeranol down regulates p53 expression in primary cultured human breast cancer epithelial cells through Epigenetic Modification
    Cancer Research, 2010
    Co-Authors: Shuhong Lin, Cheikti Kuo, Young C Lin
    Abstract:

    Despite great improvements in diagnosis, treatment advances, and healthier life-styles, breast cancer remains the most common cancer among women in the United States. It is estimated that 192,370 new cases arise and 40,170 women will die from breast cancer in 2009. Epidemiological studies have suggested that there are many risk factors associated with breast cancer such as dietary fat and environmental estrogenic endocrine disruptors. Zeranol (Z), as one of the six growth promoters approved by FDA, has been widely used to enhance the growth of beef cattle. Researchers are still in disagreement whether the growth promoters pose any adverse health risk from consuming beef products produced from Z-implanted beef cattle. Our previous results showed that pre-adipocytes isolated from the cattle 60 days post Z-implantation (72 mg/pellet/animal) grow about 12 fold faster than the pre-adipocytes isolated from the control cattle. Treatment with 0.2, 1 and 5% sera (Z-Sera) harvested from the cattle 30 days post implantation in culture medium significantly stimulated MCF-10A, a human normal breast epithelial cells, and MCF-7 cell growth. Proliferation might be caused by Z-Sera down-regulating the expression of a tumor suppressor gene, protein tyrosine phosphatase γ (PTP γ). The current study investigated the effects of Z on primary cultured human normal and cancerous breast epithelial cell growth (PCHNBECs, PCHBCECs), and the regulation of p53 expression, as well as the potential mechanism. Using non-radioactive cell proliferation assay, real time PCR and western blot analysis, we demonstrated that PCHBCECs are more sensitive in response to treatment with Z than PCHNBECs. Treatment with 7.5, 15 and 30 nM Z increased the growth of PCHNBECs at 27, 45, 50%, respectively, as compared to the control group. The same concentrations enhanced the proliferation of PCHBCECs at 25, 84 and 91%. The expression of p53 protein in PCHNBECs did not decrease by the treatment of Z. However, in PCHBCECs, treatment with 7.5, 15 and 30 nM Z significantly down-regulated the expression of p53 protein by 10, 20 and 40%, respectively. Further investigation suggests that the effect of Z on decreasing the expression of p53 in PCHBCECs might be mediated through its Epigenetic Modification. Our results showed that Z treatment up-regulates the expression of DNMT1 mRNA by 36, 58 and 160%, and protein by 14, 25 and 42% in PCHBCECs after 24 hour exposure. Our data suggest that the stimulatory effect of Z on PCHBCECs growth might be via down-regulation of p53 expression as a result of Epigenetic Modification mediated through Z enhancing the expression of DNMT1 mRNA and protein levels. These results imply the potential adverse health risks of the consumption of beef products with Z or its bio-active metabolites. Further investigation on this critical issue is in-progress in our laboratory (Supported by NIH grant R01 ES015212-01). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5364.

Tetsuji Kakutani - One of the best experts on this subject based on the ideXlab platform.

Yijing Su - One of the best experts on this subject based on the ideXlab platform.

  • emerging roles of tet proteins and 5 hydroxymethylcytosines in active dna demethylation and beyond
    Cell Cycle, 2011
    Co-Authors: Yijing Su, Guo Li Ming, Chun Zhong, Hongjun Song
    Abstract:

    Cytosine methylation is the major Epigenetic Modification of metazoan DNA. Although there is strong evidence that active DNA demethylation occurs in animal cells, the molecular details of this process are unknown. The recent discovery of the TET protein family (TET1–3) 5-methylcytosine hydroxylases has provided a new entry point to reveal the identity of the long-sought DNA demethylase. Here, we review the recent progress in understanding the function of TET proteins and 5-hydroxymethylcytosine (5hmC) through various biochemical and genomic approaches, the current evidence for a role of 5hmC as an early intermediate in active DNA demethylation and the potential functions of TET proteins and 5hmC beyond active DNA demethylation. We also discuss how future studies can extend our knowledge of this novel Epigenetic Modification.

  • emerging roles of tet proteins and 5 hydroxymethylcytosines in active dna demethylation and beyond
    Cell Cycle, 2011
    Co-Authors: Yijing Su, Guo Li Ming, Chun Zhong, Hongjun Song
    Abstract:

    Cytosine methylation is the major Epigenetic Modification of metazoan DNA. Although there is strong evidence that active DNA demethylation occurs in animal cells, the molecular details of this process are unknown. The recent discovery of the TET protein family (TET1–3) 5-methylcytosine hydroxylases has provided a new entry point to reveal the identity of the long-sought DNA demethylase. Here, we review the recent progress in understanding the function of TET proteins and 5-hydroxymethylcytosine (5hmC) through various biochemical and genomic approaches, the current evidence for a role of 5hmC as an early intermediate in active DNA demethylation and the potential functions of TET proteins and 5hmC beyond active DNA demethylation. We also discuss how future studies can extend our knowledge of this novel Epigenetic Modification.

Jessica J Connelly - One of the best experts on this subject based on the ideXlab platform.

  • Epigenetic Modification of the oxytocin receptor gene is associated with emotion processing in the infant brain
    Developmental Cognitive Neuroscience, 2019
    Co-Authors: Kathleen M Krol, Meghan H Puglia, James P Morris, Jessica J Connelly, Tobias Grossmann
    Abstract:

    Abstract The neural capacity to discriminate between emotions emerges early in development, though little is known about specific factors that contribute to variability in this vital skill during infancy. In adults, DNA methylation of the oxytocin receptor gene (OXTRm) is an Epigenetic Modification that is variable, predictive of gene expression, and has been linked to autism spectrum disorder and the neural response to social cues. It is unknown whether OXTRm is variable in infants, and whether it is predictive of early social function. Implementing a developmental neuroimaging Epigenetics approach in a large sample of infants (N = 98), we examined whether OXTRm is associated with neural responses to emotional expressions. OXTRm was assessed at 5 months of age. At 7 months of age, infants viewed happy, angry, and fearful faces while functional near-infrared spectroscopy was recorded. We observed that OXTRm shows considerable variability among infants. Critically, infants with higher OXTRm show enhanced responses to anger and fear and attenuated responses to happiness in right inferior frontal cortex, a region implicated in emotion processing through action-perception coupling. Findings support models emphasizing oxytocin’s role in modulating neural response to emotion and identify OXTRm as an Epigenetic mark contributing to early brain function.

  • Epigenetic Modification of the oxytocin receptor gene influences the perception of anger and fear in the human brain
    Proceedings of the National Academy of Sciences of the United States of America, 2015
    Co-Authors: Meghan H Puglia, James P Morris, Travis S Lillard, Jessica J Connelly
    Abstract:

    In humans, the neuropeptide oxytocin plays a critical role in social and emotional behavior. The actions of this molecule are dependent on a protein that acts as its receptor, which is encoded by the oxytocin receptor gene (OXTR). DNA methylation of OXTR, an Epigenetic Modification, directly influences gene transcription and is variable in humans. However, the impact of this variability on specific social behaviors is unknown. We hypothesized that variability in OXTR methylation impacts social perceptual processes often linked with oxytocin, such as perception of facial emotions. Using an imaging Epigenetic approach, we established a relationship between OXTR methylation and neural activity in response to emotional face processing. Specifically, high levels of OXTR methylation were associated with greater amounts of activity in regions associated with face and emotion processing including amygdala, fusiform, and insula. Importantly, we found that these higher levels of OXTR methylation were also associated with decreased functional coupling of amygdala with regions involved in affect appraisal and emotion regulation. These data indicate that the human endogenous oxytocin system is involved in attenuation of the fear response, corroborating research implicating intranasal oxytocin in the same processes. Our findings highlight the importance of including Epigenetic mechanisms in the description of the endogenous oxytocin system and further support a central role for oxytocin in social cognition. This approach linking Epigenetic variability with neural endophenotypes may broadly explain individual differences in phenotype including susceptibility or resilience to disease.