External Seminar "Heterochromatin condensates regulate DNA elimination in Tetrahymena" by Kensuke Kataoka

Speaker:

Kensuke Kataoka 
Assistant Professor, National Institute for Basic Biology, Okazaki Japan
(Visiting Scientist, Gregor Mendel Institute of Molecular Plant Biology,
Vienna Austria)

Abstract:
Heterochromatin, characterized by histone H3 methylation and recognition by HP1 proteins, plays a central role in transposon silencing. Although many eukaryotic cells express multiple HP1 proteins, their coordinated functions remain unclear. During sexual reproduction in the ciliate Tetrahymena, a subset of HP1-like proteins collaborates to eliminate transposon-derived sequences from the transcriptionally active genome. Among these, the most abundant HP1-like protein undergoes phase separation and nucleates the assembly of more than ten thousand transposon-related loci into discrete nuclear condensates. Other HP1-like proteins fine-tune condensate properties, facilitating efficient clustering of transposon loci and likely recruiting effector proteins required for DNA elimination. This cooperative condensate formation spatially confines the potentially deleterious DNA elimination process within heterochromatin bodies, thereby ensuring the faithful and robust removal of transposable elements.