Details

Autor(en) / Beteiligte

• Lisch, Damon
• Bennetzen, Jeffrey L

Titel

Transposable element origins of epigenetic gene regulation

Ist Teil von

• Current opinion in plant biology, 2011-04, Vol.14 (2), p.156-161

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2011

Quelle

ScienceDirect

Beschreibungen/Notizen

• ► TEs are abundant, enormously variable and rapidly changing in all plant genomes. ► Epigenetic processes first evolved to silence TEs and viruses. ► TE insertion near a gene can place that gene under TE-derived epigenetic control. ► Stress may awaken zombie TEs in the hetrochromatin that rise up to kill active TEs. ► Gene acquisition and degradation inside TEs may be the ongoing origin of miRNA genes. Transposable elements (TEs) are massively abundant and unstable in all plant genomes, but are mostly silent because of epigenetic suppression. Because all known epigenetic pathways act on all TEs, it is likely that the specialized epigenetic regulation of regular host genes (RHGs) was co-opted from this ubiquitous need for the silencing of TEs and viruses. With their internally repetitive and rearranging structures, and the acquisition of fragments of RHGs, the expression of TEs commonly makes antisense RNAs for both TE genes and RHGs. These antisense RNAs, particularly from heterochromatic reservoirs of ‘zombie’ TEs that are rearranged to form variously internally repetitive structures, may be advantageous because their induction will help rapidly suppress active TEs of the same family. RHG fragments within rapidly rearranging TEs may also provide the raw material for the ongoing generation of miRNA genes. TE gene expression is regulated by both environmental and developmental signals, and insertions can place nearby RHGs under the regulation (both standard and epigenetic) of the TE. The ubiquity of TEs, their frequent preferential association with RHGs, and their ability to be programmed by epigenetic signals all indicate that RGHs have nearly unlimited access to novel regulatory cassettes to assist plant adaptation.