DNA methylation in eukaryotic chromosome stability

✍ Scribed by Steven S. Smith

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 221 KB
• Volume: 4
• Category: Article
• ISSN: 0899-1987
• DOI: 10.1002/mc.2940040202

✦ Synopsis

CYTOSINE METHYLATION IN GENE REGULATION

Current evidence on the role of cytosine methylation in the DNA of eukaryotes suggests that methylation plays a role in stabilizing inactive chromatin domains. The existence of proteins that bind specifically to methylated DNA suggests that folded (condensed) chromatin acquires additional stability (i.e., is less likely to unfold, or decondense) when methylated DNA is able to interact with methylated DNA-binding proteins [ 11. This hypothesis is one of several that suggest that methylation is a top-level control (often referred to as a locking mechanism) in a multilayered system that silences genes during development [21.

While the current experimental picture has revealed an indirect link between transcriptional inactivation and DNA methylation, it does not offer a compelling reason to conclude that the primary function of DNA methylation is gene regulation. In fact, the virtual absence of 5-methylcytosine from the DNA of several organisms that undergo carefully orchestrated changes in patterns of gene expression during development (e.g., Caenorhabditis and Drosophila) strongly suggests that methylation may be completely optional in the control of gene expression.