Julia Chivu ’23

Histone modifications play an essential role in the development and adaptation of plants. Histones are proteins that are involved in the packaging of DNA into chromatin. Histone modification can result in the regulation of gene expression in response to stress, temperature, light, and pathogen attack. The majority of histone-modifying enzymes– such as histone deubiquitinases– are not able to bind DNA. As a result, scientists believe that DNA-binding transcription factors are likely recruited by these enzymes to help them locate their target sites. Histone deubiquitinases are one of the most vital histone modifying enzymes. However, the interactions between transcription factors and histone deubiquitinases have not been widely studied thus far. Thus, scientists working in the Citovsky lab at Stony Brook University have recently discovered that the Arabidopsis LSH10 protein interacts with OTLD1 histone deubiquitinases as a co-repressor complex.

OTLD1 is known for cleaving and modifying the 2B histone. In addition, the enzyme represses the expression of genes that participate in cell growth and hormone signaling. To find what proteins or transcription factors could interact with this enzyme, Arabidopsis thaliana, a type of flower, was grown in controlled conditions. The interaction between the enzyme and the protein were identified using bimolecular fluorescence complementation and fluorescence resonance energy transfer. Once the desired protein was identified from the signals produced by the fluorescence, various DNA and RNA extractions, as well as reverse transcription-quantitative PCR methods were performed.

The scientists discovered that the LSH10 acts as a transcription factor, as it has a DNA binding domain. The fluorescence methods identified that the LSH10 transcription factor is able to recognize and interact with OTLD1. More specifically, this interaction led scientists to believe that the LSH10 also acts as a transcriptional repressor, as it targets the same common gene set that OTDL1 is known to repress. It was identified that LSH10 can manipulate the OTDL1 to move toward target gene promoters since the transcription factor directly binds to those promoter regions. These findings are remarkable since the function of LSH10 was not known prior. In addition, the discovery of the co-repressor complex provides better understanding regarding the histone modification mechanism.

Works Cited: 
[1] M.S. Vo Phan, et al., Arabidopsis LSH10 transcription factor and OTLD1 histone deubiquitinase interact and transcriptionally regulate the same target genes. Commun Biol 6, 58 (2023). doi: 10.1038/s42003-023-04424-x
[2] Image retrieved from: https://commons.wikimedia.org/wiki/File:Anther_of_thale_cress_%28Arabidopsis_thaliana%29,_an_artefact.jpg