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The available data suggest that the roles of DNA methylation and histone hypoacetylation, and their relationship with each other, can vary, even within an organism.
The restriction to histone H1 of the ability to inhibit enzymic DNA methylation may account for the lower methylation levels present in the internucleosomal DNA of mammalian chromatin.
DNA methylation within gene promoters and alterations in histone modifications appear to be primary mediators of epigenetic inheritance in cancer cells.
Modifications in gene expression through methylation of DNA and remodelling of chromatin via histone proteins are believed to be the most important of the epigenetic changes.
This suggests that increased proliferation activity and associated loss of histone modification may represent a generic cause of the changes observed in cancer DNA methylation profiles.
The changes in histone modification precede the alterations in DNA methylation, suggesting that they facilitate the recruitment of DNA methyltransferases.
We conclude that DNA methylation depends on histone methylation.
We conclude that DNA methylation does not control the methylation of histone H3-K9.
Journal ArticleDOI
Muhammad Tariq, Jerzy Paszkowski 
01 Jun 2004-Trends in Genetics
259 Citations
The results of recent studies indicate intriguing links between chromatin remodeling, histone methylation, DNA methylation and RNA interference.

Related Questions

Can epigenetic changes have a lasting impact on DNA transmission?4 answersEpigenetic changes can have a lasting impact on DNA transmission. Trained immunity in macrophages involves long-term retention of stimulus-induced histone post-translational modifications (PTMs) that persist for at least 14 cell divisions after stimulus washout. Early life stress and traumatic experiences can lead to epigenetic alterations in genes regulating the hypothalamus-pituitary-adrenal axis and the immune system, which may be transmitted to subsequent generations. Adverse experiences in mothers' childhoods can be correlated with DNA methylation in peripheral blood during pregnancy and in cord blood samples from their newborn infants, indicating enduring and transmitted impacts of mothers' adverse childhood experiences on DNA methylation. Infections, such as viruses and intracellular bacteria, can manipulate host cell functions through epigenetic mechanisms, which may persist even after the initial infection has been cleared. These findings suggest that epigenetic changes can have long-lasting effects on DNA transmission.
Can epigenetic effects change the DNA?4 answersEpigenetic effects can indirectly change the DNA sequence. Epigenetic modifications, such as DNA methylation and histone modifications, can alter gene expression without changing the DNA sequence itself. These modifications can lead to DNA mutations and influence genome evolution. Epigenetic mechanisms can also suppress the movement of transposable elements and control genome expansion through gene duplication. Additionally, epigenetic modifications can affect the structure of DNA, including hydrogen-bond and stacking binding energies. The epigenome, which is the collection of all the modifications that regulate gene expression, can be influenced by various factors such as hormones, environment, age, diet, and exposure to endocrine disrupting chemicals. These modifications can be seen across generations and can have long-lasting effects on phenotypes. In cancer, epigenetic changes can control gene expression and contribute to tumor progression.
What are histone modifications?5 answersHistone modifications are chemical changes to the amino acid residues of histone proteins that regulate gene expression without altering the DNA sequence. These modifications include methylation, acetylation, phosphorylation, ubiquitination, and many others. They form a "histone code" that can be used as an epigenetic marker and play a crucial role in various cellular processes such as transcriptional regulation, DNA repair, and chromosome segregation. Histone-modifying enzymes, such as histone acetyltransferases (HATs), histone deacetylases (HDACs), and histone methyltransferases (KMTs), add or remove these modifications, thereby altering the functional profile of the epigenome. Understanding the role of histone post-translational modifications is important for preventing and treating human diseases, including cancer.
What induces changes in the epigenome?5 answersChanges in the epigenome can be induced by a variety of factors including environmental stimuli, such as exposure to cigarette smoke, chemical carcinogens, dietary contaminants, physical carcinogens like UV radiation, and lifestyle choices like smoking, alcohol consumption, excess sunlight exposure, and high fat consumption. These factors can lead to alterations in DNA methylation, histone modifications, and micro-RNAs, which are all essential mechanisms for the stable propagation of gene activity states. Additionally, epigenetic changes can be influenced by specific diseases and conditions, such as blast-induced neurotrauma and ischemia. Overall, the epigenome is highly responsive to environmental and lifestyle factors, and these changes can have significant implications for the development and progression of various diseases, including cancer.
How the changes in histone modifiction can lead to the hypomethylation of a gene?5 answersChanges in histone modification can lead to the hypomethylation of a gene through coordinated regulation at both the histone and DNA levels. Histone modifications, such as acetylation and methylation, play a critical role in gene expression and chromatin conformation. In the context of gene silencing, histone deacetylation at the promoter region can repress gene transcription. Conversely, histone hyperacetylation is associated with gene activation. The interplay between histone modifications and DNA methylation is crucial for gene regulation. DNA demethylation is necessary for maximal gene stimulation, as it allows for the dissociation of repressive complexes and the recruitment of transcriptional components. Therefore, changes in histone modifications can influence the DNA methylation status of a gene, leading to hypomethylation and subsequent gene activation.
Can epigenetic alterations alter gene expression?10 answers

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