Nucleolar association of pEg7 and XCAP-E, two members of Xenopus laevis condensin complex in interphase cells.
Cell cycle dynamics and localization of condensins--multiprotein complexes involved in late stages of mitotic chromosome condensation--were studied in Xenopus laevis XL2 cell line. Western blot analysis of synchronized cells showed that the ratio of levels of both pEg7 and XCAP-E to beta-tubulin levels remains almost constant from G1 to M phase. pEg7 and XCAP-E were localized to the mitotic chromosomes and were detected in interphase nuclei. Immunostaining for condensins and nucleolar proteins UBF, fibrillarin and B23 revealed that both XCAP-E and pEg7 are localized in the granular component of the nucleolus. Nucleolar labeling of both proteins is preserved in segregated nucleoli after 6 hours of incubation with actinomycin D (5 mg/ml), but the size of the labeled zone was significantly smaller. The data suggest a novel interphase function of condensin subunits in spatial organization of the nucleolus and/or ribosome biogenesis.
Uzbekov
Rustem
R
Groupe Structure Dynamique de la Chromatine, CNRS, UMR 6061, Faculte de Medicine, 35043 Rennes, France.
Timirbulatova
Elmira
E
Watrin
Erwan
E
Cubizolles
Fabien
F
Ogereau
David
D
Gulak
Pavel
P
Legagneux
Vincent
V
Polyakov
Vladimir Ju
VJ
Le Guellec
Katherine
K
Kireev
Igor
I
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D002466:Cell Nucleolus / Q000378:metabolism*; D002875:Chromosomes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D004527:Egg Proteins / Q000737:chemistry / Q000378:metabolism*; D007399:Interphase / Q000502:physiology*; D046911:Macromolecular Substances; D016253:Microscopy, Immunoelectron; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D029867:Xenopus Proteins; D014982:Xenopus laevis
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C116601:Eg7 protein, Xenopus; D004527:Egg Proteins; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D012335:RNA, Ribosomal; C090453:XCAP-E protein, Xenopus; D029867:Xenopus Proteins; C108312:condensin complexes; D000251:Adenosine Triphosphatases