The nucleoporin Nup98 associates with the intranuclear filamentous protein network of TPR
AUTOR(ES)
Fontoura, Beatriz M. A.
FONTE
The National Academy of Sciences
RESUMO
The Nup98 gene codes for several alternatively spliced protein precursors. Two in vitro translated and autoproteolytically cleaved precursors yielded heterodimers of Nup98-6kDa peptide and Nup98-Nup96. TPR (translocated promoter region) is a protein that forms filamentous structures extending from nuclear pore complexes (NPCs) to intranuclear sites. We found that in vitro translated TPR bound to in vitro translated Nup98 and, via Nup98, to Nup96. Double-immunofluorescence microscopy with antibodies to TPR and Nup98 showed colocalization. In confocal sections the nucleolus itself was only weakly stained but there was intensive perinucleolar staining. Striking spike-like structures emanated from this perinucleolar ring and attenuated into thinner structures as they extended to the nuclear periphery. This characteristic staining pattern of the TPR network was considerably enhanced when a myc-tagged pyruvate kinase-6kDa fusion protein was overexpressed in HeLa cells. Double-immunoelectron microscopy of these cells using anti-myc and anti-TPR antibodies and secondary gold-coupled antibodies yielded row-like arrangements of gold particles. Taken together, the immunolocalization data support previous electron microscopical data, suggesting that TPR forms filaments that extend from the NPC to the nucleolus. We discuss the possible implications of the association of Nup98 with this intranuclear TPR network for an intranuclear phase of transport.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=30632Documentos Relacionados
- Nup98 Is a Mobile Nucleoporin with Transcription-dependent DynamicsV⃞
- Disruption of the FG nucleoporin NUP98 causes selective changes in nuclear pore complex stoichiometry and function
- Nup98 Localizes to Both Nuclear and Cytoplasmic Sides of the Nuclear Pore and Binds to Two Distinct Nucleoporin Subcomplexes
- Distinct Functional Domains within Nucleoporins Nup153 and Nup98 Mediate Transcription-dependent Mobility
- Nucleoporins Nup98 and Nup214 Participate in Nuclear Export of Human Immunodeficiency Virus Type 1 Rev