Warning: The NCBI web site requires JavaScript to function. more...
Generate a file for use with external citation management software.
Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA. jay14@columbia.edu
Most of the 5-methylcytosine in mammalian DNA resides in transposons, which are specialized intragenomic parasites that represent at least 35% of the genome. Transposon promoters are inactive when methylated and, over time, C-->T transition mutations at methylated sites destroy many transposons. Apart from that subset of genes subject to X inactivation and genomic imprinting, no cellular gene in a non-expressing tissue has been proven to be methylated in a pattern that prevents transcription. It has become increasingly difficult to hold that reversible promoter methylation is commonly involved in developmental gene control; instead, suppression of parasitic sequence elements appears to be the primary function of cytosine methylation, with crucial secondary roles in allele-specific gene expression as seen in X inactivation and genomic imprinting.
Your browsing activity is empty.
Activity recording is turned off.
Turn recording back on