Login

GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]


Plants repair DNA differently from animals

For a body to grow, cells must strictly control their division and death. In mammalian cells, p53 is the transcription factor most responsible for this role. The equivalent in plants is SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), even though it does not share a common evolutionary ancestor with p53. While p53 has been exhaustively studied, much less is known about SOG1. A new study led by researchers at the Nara Institute of Science and Technology (NAIST) reports in The Plant Journal concerning the target genes of SOG1 and the key DNA sequence responsible for the binding to promoters. In addition, it shows SOG1 has an immune function, which is unlike p53.

In mammalian cells, DNA damage leads to a number of molecular events that eventually phosphorylate and activate p53. Many of the same events also phosphorylate and activate SOG1 despite the molecules being quite different, notes Professor Masaaki Umeda and Assistant Professor Naoki Takahashi, who led the study.

"SOG1 plays a crucial role in DNA damage response as p53 does in animals. Phosphorylation is necessary for the activation of both. But the amino acid sequences of SOG1 and p53 display no similarity and we do not know the target genes of SOG1," they say.

Umeda has been using Arabidopsis, a popular laboratory model, to study plant cell division. In the new study, his scientists showed that, in Arabidopsis, SOG1 is only phosphorylated and thus activated upon DNA damage. The phosphorylated SOG1 then binds to promoters of a number of genes, many of which are responsible for DNA repair and cell division. However, while both SOG1 and p53 target DNA repair genes, SOG1 showed a higher affinity for genes that conducted repair through homologous recombination. Additional study revealed that a specific palindromic DNA sequence in the target promoters was crucial for SOG1 binding.

"Considering that SOG1 and p53 regulate different sets of DNA repair-related genes, it is probable that plants and animals have distinct tendencies for activating DNA repair pathways," says Umeda.

Interestingly, while the majority of SOG1 target genes were involved in DNA repair and cell cycle control, a significant subset respond to pathogen invasion, which is unlike p53, but only if the pathogen was fungus and not bacteria. Why SOG1 targets genes that elicit an immune response only to fungal infection even though DNA damage occurs regardless of the pathogen is an open question that deserves further study say the researchers.

Umeda believes that understanding the SOG1 gene targets and the SOG1 immune function could allow for better farming through the modulation of DNA damage signaling.

"Environmental factors can cause DNA damage, which activates SOG1. If we are able to control this activation, we could control the growth of agricultural products," says Umeda.

Read the paper: Identifying the target genes of SUPPRESSOR OF GAMMA RESPONSE 1, a master transcription factor controlling DNA damage response in Arabidopsis.

Article source: NAIST.

News

Envisioning a future where all the trees in Europe disappear

Vegetation plays an important role in shaping local climate: just think of the cool shade provided by a forest or the grinding heat of the open desert.


360 degrees, 180 seconds: Technique speeds analysis of crop traits

A potted nine-leaf corn plant sits on a Frisbee-sized plate. The tandem begins rotating like the centerpiece atop a giant music box, three degrees per second, and after two minutes the plant has pirouetted to its original position.


Blue gene regulation helps plants respond properly to light

Researchers at the RIKEN Center for Sustainable Resource Science (CSRS) have discovered a process through which gene expression in plants is regulated by light. Published in Proceedings of the National Academy of Sciences USA, the study found that blue light triggers a shift in which portion of a gene is ultimately expressed.