Project description:We characterised a sperm-expressed histone variant, H2B.8 in Arabidopsis by performing ChIP-seq, RNA-seq, and Hi-C. The data show that H2B.8 is exclusively deposited to unexpressed euchromatin and that gene expression is not significantly affected either by h2b.8 mutation in sperm or overexpression in soma. The deposition of H2B.8increases the contact probability of short range intrachromosomal interactions and contacts between pericentomeric regions and chromosome arms of different chromosomes.
Project description:The conserved yeast E3 ligase Bre1 and its partner E2 Rad6 monoubiquitinate histone H2B across gene bodies during the transcription cycle. While processive ubiquitination might in principle arise from Bre1/Rad6 traveling with RNA polymerase II, we provide a different explanation. Here we implicate liquid-liquid phase separation as the underlying mechanism. Biochemical reconstitution shows that Bre1 binds the scaffold protein Lge1, whose intrinsically disordered region phase separates via dynamic, multivalent interactions. The resulting condensates comprise a core of Lge1 encapsulated by an outer catalytic shell of Bre1. This layered liquid recruits Rad6 and the nucleosomal substrate, accelerating H2B ubiquitination. In vivo, the condensate-forming region of Lge1 is required to ubiquitinate H2B in gene bodies beyond the +1 nucleosome. Our data suggest that layered condensates of histone modifying enzymes generate chromatin-associated reaction chambers with augmented catalytic activity along gene bodies. Equivalent processes may occur in human cells, causing neurological disease when impaired.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein (we do not have the data in your figures?). These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein (we do not have the data in your figures?). These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.
Project description:Chromosome translocation is known to generate oncogenes such as SS18-SSX1, but the underlying mechanism remains unknown. Here we show that enhanced phase separation acquired by translocation mediates oncogenic transformation. SSX fusion dramatically enhances the phase separation property of SS18 protein through H2AK119ub. Super condensates generated by SS18-SSX recruit acetyltransferases CBP/P300 as wild type SS18, but exclude HDACs such that H3K27ac accumulates abnormally at loci from those normally occupied by SS18, resulting aberrant silencing and activation of target genes. Consistently, we show that inhibition of H3K27ac can attenuate the tumorigenicity of the fusion oncoprotein. These results provide the first case for phase separation as a transforming event to generate oncogene and super phase separation can be targeted for cancer therapy.