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General Introductory Topics
Published in Vadim Backman, Adam Wax, Hao F. Zhang, A Laboratory Manual in Biophotonics, 2018
Vadim Backman, Adam Wax, Hao F. Zhang
Blue chromatin is a less active type of chromatin. It contains polycomb-group proteins (PcG proteins), which repress transcription in particular genes involved in the regulation of developmental processes. While some genes are still transcribed in blue chromatin, black chromatin is almost completely repressive. Black chromatin actively represses transcription of many tissue-specific genes. It is not clear how black chromatin actually silences transcription, but some evidence indicates that it is achieved through specific histone proteins (see discussion that follows) that do not allow DNA to be exposed for transcription and lamins, which are associated with nuclear membrane and interfere with transcription. Indeed, black chromatin is frequently found at the nuclear periphery.
Role of Histone Methyltransferase in Breast Cancer
Published in Meenu Gupta, Rachna Jain, Arun Solanki, Fadi Al-Turjman, Cancer Prediction for Industrial IoT 4.0: A Machine Learning Perspective, 2021
Surekha Manhas, Zaved Ahmed Khan
Conformational changes and functions of chromatin templates associated with histone also undergo histone modifications in which they play a vital specific role [7]. Methylation at the histone residue of H3K27 is mediated through the formation of PRC2 complex that is critical for polycomb silencing, regulation at the transcriptional level, mammalian X inactivation, drosophila segmentation, and tumor formation (cancer) [7]. Interestingly, after disruption of PCR2 complex, in vivo levels of H3K27me1 always remain unaffected, which indicates the effective existence of several other varied contributing histone protein methyltransferases to H3K27me1 [8,9].
Epigenotoxicity: a danger to the future life
Published in Journal of Environmental Science and Health, Part A, 2023
Farzaneh Kefayati, Atoosa Karimi Babaahmadi, Taraneh Mousavi, Mahshid Hodjat, Mohammad Abdollahi
ncRNAs are a group of RNA nucleotides involved in transcription and protein synthesis but do not translate into proteins themselves. These nucleotides play an important role in histone modification. Long non-coding RNAs (LncRNAs) with more than 200 nucleotides are one of the most important epigenetic factors. Changes in their expressions were associated with a wide range of body disorders. ncRNAs involved in almost all of the chemical processes mentioned so far, including DNA methylation and chromosome structure. They are also incorporated in histone changes. These RNAs alter the expression of different genes on sex chromosomes as well. XIST, for example, is a type of lncRNA that inactivates X-chromosomes by acting on polycomb repressive complex-2 (PRC2).[14]