title: Nuclear alterations induced by cadmium chloride and L-canavanine in HeLa S3 cells. Accumulation of perichromatin granules.
abstract: The effects of L-canavanine and cadmium on the ribonucleoprotein constituents of HeLa S3 cells have been analyzed. Both chemicals induce a similar pattern of alterations in different RNP structures as well as in both RNA and protein synthesis. Pulse and chase autoradiographic experiments reveal that both canavanine and cadmium induce a preferential inhibition of nucleolar RNA synthesis and a slowdown in the transport or processing of nucleolar and extranucleolar RNA. Nucleoli become round and compact. Accumulation of perichromatin granules and fibrils occurs, there is a depletion of interchromatin fibrils, and nuclear formations appear which seem to be involved in the morphogenesis of perichromatin granules accumulated during the treatments. The appearance of clusters of 29- to 35-nm granules might be related with a deficient assembling of constituents of perichromatin granules. The effects of different inhibitors of the transcriptional processes on the accumulation of perichromatin granules suggest that these granules represent a particular subpopulation of hnRNP.
mesh_terms: D001345:Autoradiography; D002104:Cadmium / Q000494:pharmacology*; D019256:Cadmium Chloride; D002172:Canavanine / Q000494:pharmacology*; D002466:Cell Nucleolus / Q000648:ultrastructure; D002467:Cell Nucleus / Q000187:drug effects* / Q000378:metabolism; D002843:Chromatin / Q000648:ultrastructure; D006367:HeLa Cells; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D006801:Humans; D009698:Nucleoproteins / Q000378:metabolism*; D011132:Polyribosomes / Q000187:drug effects; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism; D012332:RNA, Heterogeneous Nuclear / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D002843:Chromatin; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D009698:Nucleoproteins; D012332:RNA, Heterogeneous Nuclear; D012261:Ribonucleoproteins; D002104:Cadmium; D002172:Canavanine; D012313:RNA; D019256:Cadmium Chloride