[Ultrastructural localization of transcription sites of rRNA genes in the nucleolus of wheat].

There were no definite conclusions about transcription sites of rRNA genes in nucleoli of eukaryotes for a long time. We used the wheat as specimen and observed ultrastructure of chromatin in FC of nucleoli by conventional transmission electron microscope. And we employed anti-DNA antibodies to analyze the distribution of DNA in nucleoli, and found that DNA located in FC, DFC and the transitional region between them. Using anti-UBF antibodies to study localization of RNA polymerase I transcription factor UBF in nucleoli, we observed that UBF located in DFC and the transitional region between DFC and FC in wheat, but not in FC. Furthermore, with anti-RNA/DNA hybrid antibodies, we directly and selectively labeled the transcription sites of rRNA genes of nucleoli and revealed that it located in DFC and the transitional region between DFC and FC in wheat.