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RNA polymerase II condensate formation and association with Cajal and histone locus bodies in living human cells
Author(s) -
Imada Takashi,
Shimi Takeshi,
Kaiho Ai,
Saeki Yasushi,
Kimura Hiroshi
Publication year - 2021
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/gtc.12840
Subject(s) - biology , rna polymerase ii , cajal body , microbiology and biotechnology , histone , transcription (linguistics) , locus (genetics) , gene , rna , rna polymerase iii , gene expression , rna polymerase , genetics , promoter , linguistics , philosophy , rna splicing
In eukaryotic nuclei, a number of phase‐separated nuclear bodies (NBs) are present. RNA polymerase II (Pol II) is the main player in transcription and forms large condensates in addition to localizing at numerous transcription foci. Cajal bodies (CBs) and histone locus bodies (HLBs) are NBs that are involved in transcriptional and post‐transcriptional regulation of small nuclear RNA and histone genes. By live‐cell imaging using human HCT116 cells, we here show that Pol II condensates (PCs) nucleated near CBs and HLBs, and the number of PCs increased during S phase concomitantly with the activation period of histone genes. Ternary PC–CB–HLB associates were formed via three pathways: nucleation of PCs and HLBs near CBs, interaction between preformed PC–HLBs with CBs and nucleation of PCs near preformed CB–HLBs. Coilin knockout increased the co‐localization rate between PCs and HLBs, whereas the number, nucleation timing and phosphorylation status of PCs remained unchanged. Depletion of PCs did not affect CBs and HLBs. Treatment with 1,6‐hexanediol revealed that PCs were more liquid‐like than CBs and HLBs. Thus, PCs are dynamic structures often nucleated following the activation of gene clusters associated with other NBs.