Fig. 5
Immunogold electron microscopy transcription assay based on the incorporation of 5ā-FU into nascent RNA after 45Ā min of the intraperitoneal administration of 5ā-FU. 45d post-IR. a This PDDF (asterisk) lack of immunogold labeling indicating the absence of transcription. However, the euchromatin, including de domains flanking the PDDF appeared intensely labeled with gold particles of 5ā-FU incorporation. Scale bar: 300Ā nm. b Detailed of 5ā-FU incorporation in the euchromatin boundary of a PDDF (asterisk). Scale bar: 200Ā nm. c Detail of a PDDF (asterisk) associated with both the nucleolus (No) and a Cajal Body (CB). Note the absence of nascent RNA in the PDDF and in the transcription-free CB, whereas the nucleolus and adjacent euchromatin appeared immunogold labeled. d Immunogold electron microscopy for the active RNA polymerase II shows the absence of labeling in a PDDF (asterisk), whereas the surrounding euchromatin appeared decorated with gold particles Scale bar: 150Ā nm