In the genetic transfer from one generation to another, organisms not only share the fundamental DNA structure but also chemical indicators guiding cells on DNA interpretation. This transfer process, known as epigenetic inheritance, is especially prevalent in plants, and its understanding can impact agriculture, food availability, and ecological concerns.
Researchers from Cold Spring Harbor Laboratory (CSHL), Professors Rob Martienssen and Leemor Joshua-Tor, have delved into the mechanisms plants use to transfer markers that maintain transposons in an inactive state. These transposons, often termed "jumping genes," can be problematic if activated, as they might rearrange and potentially harm other genes. To counteract this, cells tag certain DNA sites through a process termed methylation.
The duo has elucidated the role of the protein DDM1 in preparing the ground for the enzyme responsible for marking new DNA sequences. Given the compact nature of plant DNA, it is densely packed. DNA is organized around proteins called histones to maintain this structured genome. Martienssen notes that these histones could inhibit important enzymes from accessing the DNA. For methylation to transpire, histones must be either removed or shifted.
DDM1's discovery by Martienssen and former CSHL associate Eric Richards dates back three decades. It has since been understood that DDM1 mobilizes DNA over its packing proteins to display the sites requiring methylation. Drawing a parallel, Martienssen describes this movement as a yo-yo smoothly traveling along a string, where the histones can relocate along the DNA, making certain DNA sections accessible without detaching.
Utilizing genetic and biochemical tests, Martienssen identified specific histones affected by DDM1. Concurrently, Joshua-Tor employed cryo-electron microscopy, achieving intricate visuals of the enzyme engaging with DNA and the affiliated packing proteins. The study showcased DDM1's mechanism of action with particular histones, reshaping the packed DNA structure. Joshua-Tor pointed out an unforeseen bond within DDM1 that matched the initial mutation observed decades prior.
Furthermore, the team observed that DDM1's preference for particular histones upholds epigenetic regulations through successive generations. A histone found exclusively in pollen resists DDM1's influence and functions as a marker during cellular division. This ensures the conservation of the histone's placement through plant growth stages and into subsequent generations, as highlighted by Martienssen.
Interestingly, this phenomenon might extend beyond plants. Similar proteins to DDM1 are essential for humans in sustaining DNA methylation. These findings could elucidate the mechanisms through which these proteins ensure the functionality and preservation of our genomes.
Read the original publication in Cell.
Researchers from Cold Spring Harbor Laboratory (CSHL), Professors Rob Martienssen and Leemor Joshua-Tor, have delved into the mechanisms plants use to transfer markers that maintain transposons in an inactive state. These transposons, often termed "jumping genes," can be problematic if activated, as they might rearrange and potentially harm other genes. To counteract this, cells tag certain DNA sites through a process termed methylation.
The duo has elucidated the role of the protein DDM1 in preparing the ground for the enzyme responsible for marking new DNA sequences. Given the compact nature of plant DNA, it is densely packed. DNA is organized around proteins called histones to maintain this structured genome. Martienssen notes that these histones could inhibit important enzymes from accessing the DNA. For methylation to transpire, histones must be either removed or shifted.
DDM1's discovery by Martienssen and former CSHL associate Eric Richards dates back three decades. It has since been understood that DDM1 mobilizes DNA over its packing proteins to display the sites requiring methylation. Drawing a parallel, Martienssen describes this movement as a yo-yo smoothly traveling along a string, where the histones can relocate along the DNA, making certain DNA sections accessible without detaching.
Utilizing genetic and biochemical tests, Martienssen identified specific histones affected by DDM1. Concurrently, Joshua-Tor employed cryo-electron microscopy, achieving intricate visuals of the enzyme engaging with DNA and the affiliated packing proteins. The study showcased DDM1's mechanism of action with particular histones, reshaping the packed DNA structure. Joshua-Tor pointed out an unforeseen bond within DDM1 that matched the initial mutation observed decades prior.
Furthermore, the team observed that DDM1's preference for particular histones upholds epigenetic regulations through successive generations. A histone found exclusively in pollen resists DDM1's influence and functions as a marker during cellular division. This ensures the conservation of the histone's placement through plant growth stages and into subsequent generations, as highlighted by Martienssen.
Interestingly, this phenomenon might extend beyond plants. Similar proteins to DDM1 are essential for humans in sustaining DNA methylation. These findings could elucidate the mechanisms through which these proteins ensure the functionality and preservation of our genomes.
Read the original publication in Cell.