Nuclear distribution of transcription factors in relation to sites of transcription and RNA polymerase II.
We have investigated the spatial relationship between sites containing newly synthesized RNA and domains containing proteins involved in transcription, such as RNA polymerase II and the transcription factors TFIIH, Oct1, BRG1, E2F-1 and glucocorticoid receptors, using dual immunofluorescence labelling followed by confocal microscopy on cultured cells. As expected, a high degree of colocalisation between the RNA polymerase II and sites containing newly synthesised RNA was observed. Like the newly synthesised RNA and the RNA polymerase II, we found that all the transcription factors that we studied are distributed more or less homogeneously throughout the nucleoplasm, occupying numerous small domains. In addition to these small domains, TFIIH was found concentrated in coiled bodies and Oct1 in a single large domain of about 1.5 microm in 30% of the cells in an asynchronous HeLa cell culture. Remarkably, we found little or no relationship between the spatial distribution of the glucocorticoid receptor, Oct1 and E2F-1 on the one hand and RNA polymerase II and transcription sites on the other hand. In contrast, a significant but incomplete overlap was observed between the spatial distributions of transcription sites and BRG1 and TFIIH. These results indicate that many of the transcription factor-rich nuclear domains are not actively involved in transcription. They may represent incomplete transcription initiation complexes, inhibitory complexes, or storage sites.
Grande
M A
MA
E.C. Slater Institut, BioCentrum Amsterdam, University of Amsterdam, The Netherlands.
van der Kraan
I
I
de Jong
L
L
van Driel
R
R
D002352:Carrier Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D009687:Nuclear Proteins / Q000378:metabolism; D027702:Organic Cation Transporter 1; D012313:RNA / Q000096:biosynthesis; D012319:RNA Polymerase II / Q000378:metabolism*; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D056465:Retinoblastoma-Binding Protein 1; D016196:S Phase; D015534:Trans-Activators; D050680:Transcription Factor DP1; D051758:Transcription Factor TFIIH; D014157:Transcription Factors / Q000378:metabolism*; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C088053:Dp transcription factor, Drosophila; D029721:Drosophila Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D008565:Membrane Proteins; D009687:Nuclear Proteins; D027702:Organic Cation Transporter 1; D011965:Receptors, Glucocorticoid; D056465:Retinoblastoma-Binding Protein 1; D015534:Trans-Activators; D050680:Transcription Factor DP1; D014157:Transcription Factors; D019473:Transcription Factors, TFII; D051758:Transcription Factor TFIIH; D012313:RNA; D012319:RNA Polymerase II; C084108:SMARCA4 protein, human; D004265:DNA Helicases