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Regional and temporal specialization in the nucleus: a transcriptionally‐active nuclear domain rich in PTF, Oct1 and PIKA antigens associates with specific chromosomes early in the cell cycle
Author(s) -
Pombo Ana,
Cuello Paula,
Schul Wouter,
Yoon JongBok,
Roeder Robert G.,
Cook Peter R.,
Murphy Shona
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.6.1768
Subject(s) - biology , cell nucleus , pika , nucleus , evolutionary biology , microbiology and biotechnology , genetics , cell cycle , computational biology , cell , ecology , national park
PTF (PSE‐binding transcription factor) activates transcription of snRNA and related genes. We investigated its distribution in HeLa nuclei by immunofluorescence, and found it spread throughout the nucleoplasm in small foci. In some cells, PTF is also concentrated in one, or very few, discrete regions (diameter ∼1.3 μm) that appear during G 1 phase and disappear in S phase. Oct1, a transcription factor that interacts with PTF, is also enriched in these domains; RNA polymerase II, TBP and Sp1 are also present. Each domain typically contains 2 or 3 transcription ‘factories’ where Br‐UTP is incorporated into nascent transcripts. Accordingly, we have christened this region the Oct1/PTF/transcription (OPT) domain. It colocalizes with some, but not all, PIKA domains. It is distinct from other nuclear domains, including coiled bodies, gemini bodies, PML bodies and the perinucleolar compartment. A small region on chromosome 6 (band 6p21) containing only ∼30 Mbp DNA, and chromosomes 6 and 7, associate with the domain significantly more than other chromosomes. The domains may act like nucleoli to bring particular genes on specific chromosomes together to a region where the appropriate transcription and processing factors are concentrated, thereby facilitating the expression of those genes.