Ma. Grande et al., PML-CONTAINING NUCLEAR-BODIES - THEIR SPATIAL-DISTRIBUTION IN RELATION TO OTHER NUCLEAR-COMPONENTS, Journal of cellular biochemistry, 63(3), 1996, pp. 280-291
The PML protein is a human growth suppressor concentrated in 10 to 20
nuclear bodies per nucleus (PML bodies). Disruption of the PML gene ha
s been shown to be related to acute promyelocytic leukaemia (APL). To
obtain information about the function of PML bodies we have investigat
ed the 3D-distribution of PML bodies in the nucleus of T24 cells and c
ompared it with the spatial distribution of a variety of other nuclear
components, using fluorescence dual-labeling immunocytochemistry and
confocal microscopy. Results show that PML bodies are not enriched in
nascent RNA, the splicing component U2-snRNP, or transcription factors
(glucocorticoid receptor, TFIIH, and E2F). These results show that PM
L bodies are not prominent sites of RNA synthesis or RNA splicing. We
found that a large fraction of PML bodies (50 to 80%) is closely assoc
iated with DNA replication domains during exclusively middle-late S-ph
ase. Furthermore, in most cells that we analysed we found at least one
PML body was tightly associated with a coiled body. In the APL cell l
ine NB4, the PML gene is fused with the RAR alpha gene due to a chromo
somal rearrangement. PML bodies have disappeared and the PML antigen,
i.e., PML and the PML-RAR fusion protein, is dispersed in a punctated
pattern throughout the nucleoplasm. We showed that in NB4 cells the si
tes that are rich in PML antigen significantly colocalize with sites a
t which nascent RNA accumulates. This suggests that, in contrast to no
n-APL cells, in NB4 cells the PML antigen is associated with sites of
transcription. The implications of these findings for the function of
PML bodies are consistent with the idea that PML bodies are associated
with specific genomic loci. (C) 1996 Wiley-Liss, Inc.