Effects of anti-PM-Scl 100 (Rrp6p exonuclease) antibodies on prenucleolar body dynamics at the end of mitosis.
Prenucleolar bodies (PNBs) are transitory structures which serve as building blocks for nucleoli at the transition mitosis/interphase. The assembly of PNBs and their pathway are not clearly understood. To better understand these events, the behavior of the PNB-containing PM-Scl 100 protein was compared with that of other PNB proteins. This nucleolar protein was chosen because its yeast homologue, Rrp6p exonuclease [1], is known to participate in late events in 5.8 S rRNA (ribosomal RNA) processing. There was a heterogeneous distribution of nucleolar proteins in different classes of PNBs. The PM-Scl 100 colocalized predominantly with protein B23. The PM-Scl-100-containing PNBs were translocated at later times to nucleoli as opposed to the fibrillarin-containing PNBs. Microinjections of antibodies directed against PM-Scl 100 during mitosis inhibited targeting of PM-Scl 100 to the nucleolus. However fibrillarin and protein B23 still participated in nucleolar assembly in early G1. We conclude that there are different kinds of PNBs whose translocation to the nucleoli follow ordered kinetics. Interestingly, proteins involved in late steps of processing as PM-Scl 100 are translocated late, suggesting that they are not cotranscriptionally associated with the rRNA precursors.
Fomproix
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Institut Jacques Monod, Cedex 05, Paris, 75251, France.
Hernandez-Verdun
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D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000918:Antibody Specificity; D001323:Autoantibodies / Q000494:pharmacology; D002466:Cell Nucleolus / Q000201:enzymology* / Q000648:ultrastructure; D002467:Cell Nucleus / Q000648:ultrastructure; D002478:Cells, Cultured; D002868:Chromosomal Proteins, Non-Histone / Q000302:isolation & purification; D005095:Exoribonucleases / Q000276:immunology / Q000302:isolation & purification*; D063326:Exosome Multienzyme Ribonuclease Complex; D005455:Fluorescent Antibody Technique; D007399:Interphase; D007668:Kidney / Q000166:cytology; D007614:Macropodidae; D008845:Microinjections; D008938:Mitosis; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000276:immunology / Q000302:isolation & purification*; D010750:Phosphoproteins / Q000302:isolation & purification; D012323:RNA Processing, Post-Transcriptional; D016601:RNA-Binding Proteins / Q000302:isolation & purification; D029701:Saccharomyces cerevisiae Proteins; D000097796:Nucleolin
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D002868:Chromosomal Proteins, Non-Histone; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; D009687:Nuclear Proteins; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097796:Nucleolin; C047458:fibrillarin; C112610:RRP6 protein, S cerevisiae