Proteomic and targeted analytical identification of BXDC1 and EBNA1BP2 as dynamic scaffold proteins in the nucleolus.
The nuclear matrix has classically been assumed to be a solid structure coherently aligning nuclear components, but its real nature remains obscure. We separated the proteins in a ribonucleoprotein-containing nuclear matrix fraction of HeLa cells by reversed-phase HPLC followed by SDS-PAGE, and identified 83 proteins through peptide mass fingerprint (PMF) analysis. Many nucleolar proteins, classical nuclear matrix proteins, RNA binding proteins, cytoskeletal proteins and five uncharacterized proteins were identified in this fraction. Four of the latter proteins were localized to the cell nucleus, BXDC1 and EBNA1BP2 being especially localized to the nucleolus. Fluorescence recovery after photobleaching and RNAi knockdown analyses suggested that BXDC1 and EBNA1BP2 function in a dynamic scaffold for ribosome biogenesis.
Hirano
Yasuhiro
Y
Kyoto University, Yoshida-konoe-cho, Kyoto, Japan. hirano@lif.kyoto-u.ac.jp
Ishii
Kohei
K
Kumeta
Masahiro
M
Furukawa
Kazuhiro
K
Takeyasu
Kunio
K
Horigome
Tsuneyoshi
T
D002352:Carrier Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D002466:Cell Nucleolus / Q000187:drug effects / Q000378:metabolism*; D016000:Cluster Analysis; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D015530:Nuclear Matrix / Q000737:chemistry / Q000378:metabolism; D034521:Nuclear Matrix-Associated Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D009687:Nuclear Proteins / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D020543:Proteome / Q000032:analysis; D040901:Proteomics / Q000379:methods*; D012313:RNA / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology; D016601:RNA-Binding Proteins; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism
D002352:Carrier Proteins; C432687:EBNA1BP2 protein, human; D034521:Nuclear Matrix-Associated Proteins; D009687:Nuclear Proteins; D020543:Proteome; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; C538716:RPF2 protein, human; D017411:Ribonucleoproteins, Small Nuclear; D012313:RNA