Internal Seminar: Shannon unit and Saze unit

Theory of Quantum Matter Unit (Nic Shannon)

Speaker : Nic Shannon

Title : Shedding light on frustrated magnets in high magnetic field

Abstract : The search for new quantum phases and excitations is central to modern condensed matter physics. In this context, frustrated magnets have proved a particularly rich source of inspiration. Using the cubic spinel Cd2Cr2O7 as an example, we discuss some of the new types of quantum phase which can arise in frustrated magnets in high magnetic field, and how optical experiments have helped inform our understanding of these systems.

Plant Epigenetics Unit (Hidetoshi Saze)

Speaker : Ngoc Tu Le

Title : Epigenetic regulation of intragenic transposons impacts on gene transcription in Arabidopsis thaliana.

Abstract : Genomes of higher eukaryotes, including plants, comprise a large amount of transposable elements (TEs), which are often silenced by epigenetic mechanisms such as histone posttranslational modifications and DNA methylation. Although silencing of TEs imposes deleterious effects on expression of nearby genes, recent studies reveal the presence of intragenic TEs marked by repressive epigenetic marks within actively transcribed genes. Even for the well-studied plant model Arabidopsis thaliana, however, how intragenic TEs are epigenetically regulated, and their potential impacts on host gene expression, remain largely unexplored.

Using in-house and publicly available data, we comprehensively analyzed genome-wide distribution and epigenetic regulation of intragenic TEs in A. thaliana. Our analysis revealed that about 7% of TEs are located within gene bodies, almost equally distributed between intronic and exonic regions. Most of them are short and less methylated than their intergenic copies. Interestingly, while exonic TEs are epigenetically targeted in the same manner as genes, intronic TEs are regulated similarly to intergenic TEs. Moreover, expression analysis showed that heterochromatic epigenetic marks associated with intronic TEs are critical for proper transcription of the associated genes. The analysis provides the first insight into how epigenetic regulation of intragenic TEs affects transcriptional landscape of the A. thaliana genome, and suggests the importance of epigenetic mechanisms for regulation of TEs within transcriptional gene units.