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#epigenetic regulation

2 public questions tagged with this topic.

Regulation of chromatin structure

Which histone variant is linked with inactive X chromosome?

Histone variants mark chromosome-wide silencing programs. While macroH2A is best characterized for Barr body enrichment, ubiquitylated forms of H2A.Z have been detected on facultative heterochromatin of inactive X in female mammalian cells, colocalizing with H3K27me3, loss of H4 acetylation and DNA methylation. This variant participates in dynamic relocalization of HP1 and establishment of facultative heterochromatin post-meiosis, replacing macroH2A at certain developmental stages. Its presence reflects context-dependent roles beyond active promoters, contributing to stable propagation of X-chromosome inactivation through recruitment of PRC2 and transcriptional repressor complexes.

Ref: Sarcinella et al., Nature, H2A.Z Ubiquitylation Enriched on Inactive X Chromosome, Facultative Heterochromatin

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DNA

Which base modification is associated with epigenetic regulation in eukaryotic DNA?

5-Methylcytidine is the scientifically accurate answer to this question. Within the study of Nucleic Acid, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of 5-Methylcytidine directly address what is being asked. Among the other options, Pseudouridine, Hypoxanthine, and Uridine do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.

Ref: Campbell Biology, Urry et al., 12th Ed.

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