Involvement of transposons in epigenetic regulation of embryogenesis

Abstract

The systems that control DNA methylation and histone modifications in embryonic development are still considered unknown, although their study is promising for the development of stem cell genetics. This review article is devoted to the description of evidence that the drivers of changes in epigenetic factors of stem cells in their successive divisions are species-specific patterns of activation of transposable elements formed in evolution. These patterns are due to the sensitivity of transposons to the influence of the microenvironment and environmental factors, as well as the functioning of their processed transcripts as noncoding RNAs. A large amount of evidence has been accumulated that many protein-coding genes originate from transposable elements, including those involved in DNA methylation and histone modification. Moreover, transposons are key sources of binding sites for transcription factors, promoters, enhancers, silencers, insulators, as well as small and long non-coding RNAs that have an epigenetic effect on gene expression at the transcriptional and post-transcriptional levels. In evolution, transposons were the sources of origin for spliceoso-mal introns and components of the spliceosome, alternative sites and regulators of splicing. The identification of specific transposons that serve as drivers of stem cells at certain stages can become the basis for their optimal control using noncoding RNAs.