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© The Rockefeller University Press,
0021-9525/2000//949 $5.00
The Journal of Cell Biology, Volume 150, Number 5,
, 2000 949-962
Original Article |
The ER Repeat Protein Yt521-B Localizes to a Novel Subnuclear Compartment
stefan{at}stamms-lab.net
The characterization of distinct subnuclear domains suggests a dynamic nuclear framework supporting gene expression and DNA replication. Here, we show that the glutamic acid/arginine-rich domain protein YT521-B localizes to a novel subnuclear structure, the YT bodies. YT bodies are dynamic compartments, which first appear at the beginning of S-phase in the cell cycle and disperse during mitosis. Furthermore, in untreated cells of the human cell line MCF7 they were undetectable and appeared only after drug- induced differentiation. YT bodies contain transcriptionally active sites and are in close contact to other subnuclear structures such as speckles and coiled bodies. YT bodies disperse upon actinomycin D treatment, whereas other transcriptional inhibitors such as
-amanitin or DRB have little effect. On the basis of our experiments, we propose that YT521-B may participate in the assembly of genes into transcription centers, thereby allowing efficient regulation of gene expression.
Key Words: subnuclear compartments transcription cell cycle MCF7 differentiation actinomycin D
© 2000 The Rockefeller University Press
Abbreviations used in this paper: DRB, 5,6-dichloro-1-β-ribofuranosyl-benzimidazole; EGFP, enhanced green fluorescent protein; HNTG, Hepes/NaCl/Triton X-100/Glycerol; OPT, Oct1/PTF/transcription domain; PML, promyelocytic leukemia protein; PP1, [4-amino-5-(4-methylphenyl)-7-(t-butyl) pyrazolo [3,4-d]-pyrimidine; RIPA, radioimmune precipitation assay; SAF-B, scaffold attachment factor B; SAR/MAR region, scaffold attachment/matrix attachment region; SR protein, serine/arginine-rich protein.
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